ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Articles  (19,594)
  • Springer  (19,594)
  • 2005-2009  (7,961)
  • 2000-2004  (7,424)
  • 1980-1984  (2,863)
  • 1965-1969  (1,346)
  • Computer Science  (19,594)
Collection
  • Articles  (19,594)
Years
Year
Journal
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 19 (1980), S. 300-312 
    ISSN: 1436-4646
    Keywords: Equilibrium Prices ; Nonconvex Mathematical Programming ; Shadow Prices
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract In this paper a definition is proposed for the concept of shadow prices in nonconvex programming. For a nonlinear program with equality and inequality constraints, existence of these prices and bounds for their possible values are obtained under the Mangasarian—Fromowitz regularity condition. Their exact values and some continuity properties are obtained under the more restrictive linear independence regularity condition. A definition of equilibrium prices is also proposed. Under convexity assumptions, all definitions and results coincide with those already known on this subject in convex programming.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 19 (1980), S. 313-327 
    ISSN: 1436-4646
    Keywords: Retrogressing Paths ; Homotopy Method ; Fixed-point Algorithm
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract For certain functionsf fromR n toR n , the Eaves—Saigal algorithm computes a path inR n × (0, 1] which converges to a zero off. In this case, it is shown that even whenf is of classC ∞ and has a unique zero, the converging path may retrogress infinitely many times.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 21 (1981), S. 190-203 
    ISSN: 1436-4646
    Keywords: Complementarity Problem ; Cones ; Topological Degree
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract In this paper we consider the problem of establishing the number of solutions to the complementarity problem. For the case when the Jacobian of the mapping has all principal minors negative, and satisfies a condition at infinity, we prove that the problem has either 0, 1, 2 or 3 solutions. We also show that when the Jacobian has all principal minors positive, and satisfies a condition at infinity, the problem has a unique solution.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 21 (1981), S. 233-234 
    ISSN: 1436-4646
    Keywords: Polytope ; Subdivision ; Simplex ; Volume ; Centroid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract Subdivisions of polytopes are described which place any chosen vertex in a (near-) minimal number of simplices. Ancillary procedures to find volumes and centroids of polytopes are indicated.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 21 (1981), S. 301-318 
    ISSN: 1436-4646
    Keywords: Semi-infinite Programs ; Open Helly-type Theorems ; Finite Subprograms ; Convex Programs ; Multi-criteria Programs ; Quasi-convex Programs ; Quasi-differentiable Programs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract We show that a semi-infinite quasi-convex program with certain regularity conditions possesses finitely constrained subprograms with the same optimal value. This result is applied to various problems.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 21 (1981), S. 348-356 
    ISSN: 1436-4646
    Keywords: Multi-extremal Optimization ; Multinomial Distribution ; Bayes Estimate ; Monte Carlo
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract The solution of ak-extremal problem is defined as the set of pairs (x i * , θi),i = 1, ⋯ ,k, where x t * isi th local minimum andθ i is the volume of the set of attraction of this minimum. A Bayesian estimate ofk and (θ 1 , ⋯ , θ k ) is constructed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 22 (1982), S. 71-81 
    ISSN: 1436-4646
    Keywords: Blocking ; Antiblocking ; Polarity ; Penumbra
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract E. Johnson has recently shown that the concept of a penumbra leads to a simple geometric description of the blocker and antiblocker of a given set. Here we develop some basic results on penumbras which permit us to slightly generalize and simplify results on their relationship to blocking and antiblocking theory. In addition, motivated by the obvious symmetry of our results, we examine the effect of reversing the blocking and antiblocking operations.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 22 (1982), S. 121-121 
    ISSN: 1436-4646
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 22 (1982), S. 148-162 
    ISSN: 1436-4646
    Keywords: Set Covering Problem ; Median Problem ; Location Problems ; Heuristics ; Worst Case Analysis ; Continuous Location Problem
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract We describe in this paper polynomial heuristics for three important hard problems—the discrete fixed cost median problem (the plant location problem), the continuous fixed cost median problem in a Euclidean space, and the network fixed cost median problem with convex costs. The heuristics for all the three problems guarantee error ratios no worse than the logarithm of the number of customer points. The derivation of the heuristics is based on the presentation of all types of median problems discussed as a set covering problem.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 22 (1982), S. 227-230 
    ISSN: 1436-4646
    Keywords: Minimax ; Nonconvex Optimization ; Stationary Points
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract We give a short proof that in a convex minimax optimization problem ink dimensions there exist a subset ofk + 1 functions such that a solution to the minimax problem with thosek + 1 functions is a solution to the minimax problem with all functions. We show that convexity is necessary, and prove a similar theorem for stationary points when the functions are not necessarily convex but the gradient exists for each function.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 18 (1980), S. 186-196 
    ISSN: 1436-4646
    Keywords: Weber's Problem ; Weiszfeld's Method ; Optimal Location
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract For solving the Euclidean distance Weber problem Weiszfeld proposed an iterative method. This method can also be applied to generalized Weber problems in Banach spaces. Examples for generalized Weber problems are: minimal surfaces with obstacles, Fermat's principle in geometrical optics and brachistochrones with obstacles.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 18 (1980), S. 84-88 
    ISSN: 1436-4646
    Keywords: Complementary Pivot Algorithms ; Triangulations ; Vector Labels ; Borsuk's Theorem on Antipodal Points
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract In this short note a simple and constructive proof is given for Borsuk's theorem on antipodal points. This is done through a special application of the complementary pivoting algorithm.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 13
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 18 (1980), S. 110-110 
    ISSN: 1436-4646
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 18 (1980), S. 155-168 
    ISSN: 1436-4646
    Keywords: Constrained Optimization ; Differential Equation ; Global Solution ; Nonlinear Programming
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract A new method is presented for finding a local optimum of the equality constrained nonlinear programming problem. A nonlinear autonomous system is introduced as the base of the theory instead of usual approaches. The relation between critical points and local optima of the original optimization problem is proved. Asymptotic stability of the critical points is also proved. A numerical algorithm which is capable of finding local optima systematically at the quadratic rate of convergence is developed from a detailed analysis of the nature of trajectories and critical points. Some numerical results are given to show the efficiency of the method.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 15
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 18 (1980), S. 215-227 
    ISSN: 1436-4646
    Keywords: Frank—Wolfe Theorem ; Quadratic Programming ; Norm Coercive Functions ; Polyhedral Sets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract The Frank—Wolfe theorem states that a quadratic function, bounded below on a nonempty polyhedral convex set, attains its infimum there. This paper gives sufficient conditions under which a function either attains its infimum on a nonempty polyhedral convex set or is unbounded below on some halfline of that set. Quadratic functions are shown to satisfy these sufficient conditions.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 16
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 18 (1980), S. 248-273 
    ISSN: 1436-4646
    Keywords: Legendre Transform ; Stationary Points ; Convex Functions ; Duality
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract In this work non-convex programs are analyzed via Legendre transform. The first part includes definitions and the classification of programs that can be handled by the transformation. It is shown that differentiable functions that are represented as a sum of strictly concave and convex functions belong to this class. Conditions under which a function may have such representation are given. Pseudo duality is defined and the pseudo duality theorem for non linear programs with equality constraints is proved. The techniques described are constructive ones, and they enable tocalculate explicitly a pseudo dual once the primal program is given. Several examples are included. In the convex case these techniques enable the explicit calculation of the dual even in cases where direct calculation was not possible.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 17
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 18 (1980), S. 286-290 
    ISSN: 1436-4646
    Keywords: Facility Location ; Steiner's Problem ; Location on the Sphere
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract This note describes the nature of optimal solutions for the spherical Steiner-Weber location problem for the case of unit weights and either 3 or 4 demand points (requireing 4 demand points to lie in an open hemisphere). Geometrically appealing results which are necessary conditions for optimum solutions and spherical analogs of known planar results are obtained.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 18
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 24 (1982), S. 257-268 
    ISSN: 1436-4646
    Keywords: Nondifferentiable Programming ; Convex Analysis ; Sensivity Analysis ; Duality Theory ; Second Order Derivative ; Second Order Methods
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract We study differential properties of the support function of the∈-subdifferential of a convex function; applications in algorithmics are also given.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 19
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 18 (1980), S. 62-67 
    ISSN: 1436-4646
    Keywords: Economic Interpretation ; Mathematical Programming ; Duality ; Stochastic Programming
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract The purpose of this note is to interpret a class of stochastic programming problems in economic terms. The primal stochastic program is shown to represent a certain production program of an entrepreneur. The dual program, which is also a stochastic program, represents the problem of a contractor who desires to purchase the entrepreneur's resources and sell product back to him.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 20
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 21 (1981), S. 120-120 
    ISSN: 1436-4646
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 21
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 21 (1981), S. 319-330 
    ISSN: 1436-4646
    Keywords: Nonlinear Programming ; Geometric Programming ; Duality Theory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract The several published methods for mapping a dual solution estimate to a primal solution estimate in posynomial geometric programming provide no criteria for deciding how much deviation from primal feasibility, or discrepancy between the primal and dual objective function values, should be permitted before the primal solution estimate is accepted by the designer. This paper presents a new and simple dual-to-primal conversion method that uses the cost coefficients to provide a sound economic criterion for determining when to accept a primal solution estimate. The primal solution estimate generated is the exact solution to a modified primal obtained from the given primal by modifying the cost coefficients, with the exponent matrix left unchanged. The method is shown to have desirable properties when coupled with a convergent dual algorithm.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 22
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 22 (1982), S. 93-103 
    ISSN: 1436-4646
    Keywords: Linear Programming ; Relaxation Method ; Polynomiality
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract A class of linear programs is given in which the relaxation method for inequalities, under the same operating rules as Khacian's method, is not polynomial in the length of the input. This result holds for any value of the relaxation parameter.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 23
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 22 (1982), S. 117-120 
    ISSN: 1436-4646
    Keywords: Augmenting Path Algorithm ; Boolean Lattice ; Jordan-Hölder Theorem ; Matroid Intersection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract It is noted that the decomposition of a network presented by J.C. Picard and M. Queyranne through an algorithmic argument may be defined from a general lattice-theoretic result for more general problems for which the equalities of maximum-flow minimum-cut type hold.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 24
    ISSN: 1436-4646
    Keywords: Geometric Programming ; Code Comparisons ; Numerical Testing ; Nonlinear Programming
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract Ten codes or code variants were used to solve the five equivalent posynomial GP problem formulations. Four of these codes were general NLP codes; six were specialized GP codes. A total of forty-two test problems was solved with up to twenty randomly generated starting points per problem. The convex primal formulation is shown to be intrinsically easiest to solve. The general purpose GRG code called OPT appears to be the most efficient code for GP problem solution. The reputed superiority of the specialized GP codes GGP and GPKTC appears to be largely due to the fact that these codes solve the convex primal formulation. The dual approaches are only likely to be competitive for small degree of difficulty, tightly constrained problems.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 25
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 22 (1982), S. 231-235 
    ISSN: 1436-4646
    Keywords: Integer Programming ; Covering
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract LetA be a non-negative matrix with integer entries and no zero column. The integer round-up property holds forA if for every integral vectorw the optimum objective value of the generalized covering problem min{1y: yA ≥ w, y ≥ 0 integer} is obtained by rounding up to the nearest integer the optimum objective value of the corresponding linear program. A polynomial time algorithm is presented that does the following: given any generalized covering problem with constraint matrixA and right hand side vectorw, the algorithm either finds an optimum solution vector for the covering problem or else it reveals that matrixA does not have the integer round-up property.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 26
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 21 (1981), S. 1-18 
    ISSN: 1436-4646
    Keywords: Game Theory ; Cost Allocation ; Spanning Tree
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract We consider the problem of cost allocation among users of a minimum cost spanning tree network. It is formulated as a cooperative game in characteristic function form, referred to as a minimum cost spanning tree (m.c.s.t.) game. We show that the core of a m.c.s.t. game is never empty. In fact, a point in the core can be read directly from any minimum cost spanning tree graph associated with the problem. For m.c.s.t. games with efficient coalition structures we define and construct m.c.s.t. games on the components of the structure. We show that the core and the nucleolus of the original game are the cartesian products of the cores and the nucleoli, respectively, of the induced games on the components of the efficient coalition structure.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 27
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 21 (1981), S. 119-119 
    ISSN: 1436-4646
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 28
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 21 (1981), S. 121-136 
    ISSN: 1436-4646
    Keywords: Linear Programming ; Polynomial Algorithms ; Total Unimodularity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract This paper describes several algorithms for solution of linear programs. The algorithms are polynomial when the problem data satisfy certain conditions.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 29
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 21 (1981), S. 182-189 
    ISSN: 1436-4646
    Keywords: Equilibrium ; Linear Monetary Economy ; Linear Programming
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract An algorithm is presented for computing equilibria in a linear monetary economy, that is, an exchange economy in which all individuals have linear utility functions and in which goods are bought and sold only in exchange for money. The algorithm computes the equilibrium prices by solving a finite sequence of linear programming problems.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 30
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 21 (1981), S. 229-232 
    ISSN: 1436-4646
    Keywords: Primal Feasible Basis ; Dual Feasible Basis ; Basic Variable ; Nonbasic Variable ; Optimal Basic Solution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract In a recent paper M.C. Cheng proposed new criteria for the simplex algorithm which guarantee that (i) a nonbasic variable of a basic feasible solution will remain nonbasic in an optimal basic solution, (ii) a basic variable of a basic solution will remain basic in an optimal basic solution. This comment gives (i) a slight generalization of the first result and (ii) a counterexample to the second proposition.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 31
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 21 (1981), S. 240-240 
    ISSN: 1436-4646
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 32
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 21 (1981), S. 241-261 
    ISSN: 1436-4646
    Keywords: Dual problem ; Duality Theory ; Optimality Conditions ; Price Functions ; Nonlinear Programming ; Integer Programming
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract We survey some recent developments in duality theory with the idea of explaining and unifying certain basic duality results in both nonlinear and integer programming. The idea of replacing dual variables (prices) by price functions, suggested by Everett and developed by Gould, is coupled with an appropriate dual problem with the consequence that many of the results resemble those used in linear programming. The dual problem adopted has a (traditional) economic interpretation and dual feasibility then provides a simple alternative to concepts such as conjugate functions or subdifferentials used in the study of optimality. In addition we attempt to make precise the relationship between primal, dual and saddlepoint results in both the traditional Lagrangean and the more general duality theories and to see the implications of passing from prices to price functions. Finally, and perhaps surprisingly, it appears that all the standard algorithms terminate by constructing primal and dual feasible solutions of equal value, i.e., by satisfying generalised optimality conditions.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 33
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 21 (1981), S. 358-358 
    ISSN: 1436-4646
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 34
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 22 (1982), S. 12-38 
    ISSN: 1436-4646
    Keywords: Graph ; Matching ; Branching ; Linear Programming ; Polyhedron
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract Matching forests generalize branchings in a directed graph and matchings in an undirected graph. We present an efficient algorithm, the PMF Algorithm, for the problem: given a mixed graphG and a real weight on each of its edges, find a perfect matching forest of maximum weight-sum. The PMF Algorithm proves the sufficiency of a linear system which definesP = (G) andP(G), the convex hull of incidence vectors of perfect matching forests and matching forests respectively ofG. The algorithm also provides a generalization of Tutte's theorem on the existence of perfect matchings in an undirected graph.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 35
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 22 (1982), S. 122-123 
    ISSN: 1436-4646
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 36
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 22 (1982), S. 141-147 
    ISSN: 1436-4646
    Keywords: Integer Rounding ; Pluperfect Graphs ; Combinatorial Optimization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract LetA be a nonnegative integral matrix with no zero columns. Theinteger round-up property holds forA if for each nonnegative integral vectorw, the solution value to the integer programming problem min{1 ⋅y: yA ≥ w, y ≥ 0, y integer} is obtained by rounding up to the nearest integer the solution value to the corresponding linear programming problem min{1 ⋅y: yA ≥ w, y ≥ 0}. Theinteger round-down property is similarly defined for a nonnegative integral matrixB with no zero rows by considering max{1 ⋅y: yB ≤ w, y ≥ 0, y integer} and its linear programming correspondent. It is shown that the integer round-up and round-down properties can be checked through a finite process. The method of proof motivates a new and elementary proof of Fulkerson's Pluperfect Graph Theorem.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 37
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 22 (1982), S. 236-237 
    ISSN: 1436-4646
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 38
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 22 (1982), S. 304-315 
    ISSN: 1436-4646
    Keywords: Location Theory ; Tree Networks ; Rigid Circuit Graphs ; Polynomial Algorithms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract We discuss several forms of thep-center location problems on an undirected tree network. Our approach is based on utilizing results for rigid circuit graphs to obtain polynomial algorithms for solving the model. Duality theory on perfect graphs is used to define and solve the dual location model.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 39
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 23 (1982), S. 111-116 
    ISSN: 1436-4646
    Keywords: Multicriteria Optimization ; Convex Analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract Existence and characterization theorems for the efficient (nondominated) set of decisions inR n are presented. The existence is proved when the set of decisions satisfies some compactness conditions. The efficient set is characterized in terms of the exposed efficient decisions when certain convexity and compactness conditions are satisfied.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 40
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 23 (1982), S. 170-180 
    ISSN: 1436-4646
    Keywords: Set Covering ; Heuristic Algorithms ; Worst Case Analysis ; Bounds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract In [2], Chvatal provided the tight worst case bound of the set covering greedy heuristic. We considered a general class of greedy type set covering heuristics. Their worst case bounds are dominated by that of the greedy heuristic.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 41
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 23 (1982), S. 216-226 
    ISSN: 1436-4646
    Keywords: Nonsmooth Optimization ; Subgradient ; Subdifferential ; Bundle Type Method ; Deletion Rule ; Resetting
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract A numerical method for the unconstrained minimization of a convex nonsmooth function of several variables is presented. It is closely related to the ‘bundle type’ approach and to the conjugate subgradient method. A way is suggested to reduce the amount of information to be stored during the computational procedure. Global convergence of the method to the minimum is proved.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 42
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 23 (1982), S. 326-340 
    ISSN: 1436-4646
    Keywords: Optimization ; Quasi-Newton ; Conjugate Gradient
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract In this paper we study conjugate gradient algorithms for large optimization problems. These methods accelerate (or precondition) the conjugate gradient method by means of quasi-Newton matrices, and are designed to utilize a variable amount of storage, depending on how much information is retained in the quasi-Newton matrices. We are concerned with the behaviour of such methods on the underlying quadratic model, and in particular, with finite termination properties.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 43
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 23 (1982), S. 357-360 
    ISSN: 1436-4646
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 44
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 18 (1980), S. 138-145 
    ISSN: 1436-4646
    Keywords: Set-covering Problem ; Branch and Bound ; Lower Bounds ; Steiner Triple Systems
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract Fulkerson et al. have given two examples of set covering problems that are empirically difficult to solve. They arise from Steiner triple systems and the larger problem, which has a constraint matrix of size 330 × 45 has only recently been solved. In this note, we show that the Steiner triple systems do indeed give rise to a series of problems that are probably hard to solve by implicit enumeration. The main result is that for ann variable problem, branch and bound algorithms using a linear programming relaxation, and/or elimination by dominance require the examination of a super-polynomial number of partial solutions
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 45
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 18 (1980), S. 228-228 
    ISSN: 1436-4646
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 46
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 18 (1980), S. 232-232 
    ISSN: 1436-4646
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 47
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 18 (1980), S. 308-329 
    ISSN: 1436-4646
    Keywords: Polytopes ; Linear Programming
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract This paper provides answers to several questions raised by V. Klee regarding the efficacy of Mattheiss' algorithm for finding all vertices of convex polytopes. Several results relating to the expected properties of polytopes are given which indicate thatn-polytopes defined by “large” numbers of constraints are difficult to obtain by random processes, the expected value of the number of vertices of polytope is considerably less than Klee's least upper bound the expected performance of Mattheiss' algorithm is far better than Klee's upper bound would suggest.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 48
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 88 (2000), S. 223-253 
    ISSN: 1436-4646
    Keywords: Mathematics Subject Classification (1991): 90C31, 41A50, 90C47
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract. In this paper, we introduce the exact order of Hoffman’s error bounds for approximate solutions of elliptic quadratic inequalities. Elliptic quadratic inequalities are closely related to Chebyshev approximation of vector-valued functions (including complex-valued functions). The set of Chebyshev approximations of a vector-valued function defined on a finite set is shown to be Hausdorff strongly unique of order exactly 2 s for some nonnegative integer s. As a consequence, the exact order of Hoffman’s error bounds for approximate solutions of elliptic quadratic inequalities is exactly 2 -s for some nonnegative integer s. The integer s, called the order of deficiency (which is computable), quantifies how much the Abadie constraint qualification is violated by the elliptic quadratic inequalities.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 49
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 88 (2000), S. 255-275 
    ISSN: 1436-4646
    Keywords: Key words: error bounds – Hölder error bound – semi–infinite program – convex inequalities – dual solutions – projection multipliers – weak Slater condition – Mangasarian–Fromovitz condition Mathematics Subject Classification (1991): 20E28, 20G40, 20C20
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract. The feasible set of a convex semi–infinite program is described by a possibly infinite system of convex inequality constraints. We want to obtain an upper bound for the distance of a given point from this set in terms of a constant multiplied by the value of the maximally violated constraint function in this point. Apart from this Lipschitz case we also consider error bounds of Hölder type, where the value of the residual of the constraints is raised to a certain power.¶We give sufficient conditions for the validity of such bounds. Our conditions do not require that the Slater condition is valid. For the definition of our conditions, we consider the projections on enlarged sets corresponding to relaxed constraints. We present a condition in terms of projection multipliers, a condition in terms of Slater points and a condition in terms of descent directions. For the Lipschitz case, we give five equivalent characterizations of the validity of a global error bound.¶We extend previous results in two directions: First, we consider infinite systems of inequalities instead of finite systems. The second point is that we do not assume that the Slater condition holds which has been required in almost all earlier papers.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 50
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 87 (2000), S. 265-280 
    ISSN: 1436-4646
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract. In the mid-1960’s, Davidon’s method was brought to the author’s attention by M.J.D. Powell, one of its earliest proponents. Its great efficacy in solving a rather difficult computational problem in which the author was involved led to an attempt to find a “best” updating formula. “Best” seemed to suggest “least” in the sense of some norm, to further the stability of the method. This led to the idea of minimizing a generalized quadratic (Frobenius) norm with the quasi-Newton and symmetry constraints on the updates. Several interesting formulas were derived, including the Davidon-Fletcher-Powell formula (as shown by Goldfarb). This approach was extended to the derivation of updates requiring no derivatives, and to Broyden-like updates for the solution of simultaneous nonlinear equations. Attempts were made to derive minimum-norm corrections in product-form updates, with an eye to preserving positive-definiteness. In the course of this attempt, it was discovered that the DFP formula could be written as a product, leading to some interesting theoretical developments. Finally, a linearized product-form update was developed which was competitive with the best update (BFGS) of that time.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 51
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 87 (2000), S. 303-316 
    ISSN: 1436-4646
    Keywords: Key words: nonlinear programming – interior-point methods – nonconvex optimization – predictor-corrector – matrix ordering
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract. The paper extends prior work by the authors on loqo, an interior point algorithm for nonconvex nonlinear programming. The specific topics covered include primal versus dual orderings and higher order methods, which attempt to use each factorization of the Hessian matrix more than once to improve computational efficiency. Results show that unlike linear and convex quadratic programming, higher order corrections to the central trajectory are not useful for nonconvex nonlinear programming, but that a variant of Mehrotra’s predictor-corrector algorithm can definitely improve performance.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 52
    Electronic Resource
    Electronic Resource
    Springer
    Computing 1 (1966), S. 50-61 
    ISSN: 1436-5057
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung Es werden Endliche Automaten betrachtet, deren Übergangsmatrix block-stochastisch ist. Die block-stochastische Struktur definiert eine Äquivalenzbeziehung zwischen Zuständen des Automaten. Die Bedeutung und Auswirkung dieser Relation wird untersucht, und zwar insbesonders in Hinsicht auf die in den einzelnen Zuständen des Automaten angenommenen Sprachen.
    Notes: Summary Finite automata are considered whose transition matrix is blockstochastic. The block-stochastic structure defines an equivalence relation among states of the automata. The implications of this relation are investigated, especially with respect to the languages accepted in the states of the automata.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 53
    Electronic Resource
    Electronic Resource
    Springer
    Computing 1 (1966), S. 88-92 
    ISSN: 1436-5057
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 54
    Electronic Resource
    Electronic Resource
    Springer
    Computing 1 (1966), S. 119-126 
    ISSN: 1436-5057
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Summary This paper gives a contribution to the hypothesis ofLense regarding the movements of the second order zeros of the derivativesI′ ν (z) of Bessel functions for every negativ variable ν.
    Notes: Zusammenfassung Die Arbeit liefert einen Beitrag zur derLense'schen Vermutung über die Bewegung der Doppelnullstellen der AbleitungI′ ν (z) der Besselfunktionen bei veränderlichem negativen ν.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 55
    Electronic Resource
    Electronic Resource
    Springer
    Computing 1 (1966), S. 133-145 
    ISSN: 1436-5057
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Summary In linear programming often it is important whether a given linear programming problem is equivalent to a transportation problem. In this case, the stepping-stone method could be taken for solving the problem, instead of the simplex method, which requires more storage capacity and computing time.—To decide this question a so-called simplex matrix is used, which results from the given linear programming problem treated by the simplex method. By help of two necessary conditions as well as a necessary and sufficient condition it can be concluded whether the linear programming problem belonging to that simplex matrix is equivalent to a transportation problem or not.—The practical handling of the developed algorithm is shown by an example.
    Notes: Zusammenfassung In der linearen Planungsrechnung interessiert oft, ob ein gegebenes lineares Optimierungsproblem sogar ein Transportproblem ist. Dann könnte man nämlich zur Lösung des Problems statt der Simplexmethode die Stepping-Stone-Methode anwenden, die weniger Speicherplatz und Rechenzeit erfordert.—Zur Klärung dieser Frage geht man von einer sogenannten Simplexmatrix aus, die aus dem mit der Simplexmethode behandelten linearen Optimierungsproblem entstanden ist. Mit Hilfe von zwei notwendigen Bedingungen sowie einer notwendigen und hinreichenden Bedingung läßt sich dann entscheiden, ob das zu jener Simplexmatrix gehörige lineare Optimierungsproblem ein Transportproblem ist oder nicht.—Die praktische Handhabung des entwickelten Verfahrens wird an einem Beispiel gezeigt.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 56
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 88 (2000), S. 411-424 
    ISSN: 1436-4646
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract. Optimal solutions of Linear Programming problems may become severely infeasible if the nominal data is slightly perturbed. We demonstrate this phenomenon by studying 90 LPs from the well-known NETLIB collection. We then apply the Robust Optimization methodology (Ben-Tal and Nemirovski [1–3]; El Ghaoui et al. [5, 6]) to produce “robust” solutions of the above LPs which are in a sense immuned against uncertainty. Surprisingly, for the NETLIB problems these robust solutions nearly lose nothing in optimality.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 57
    Electronic Resource
    Electronic Resource
    Springer
    Computing 1 (1966), S. 197-213 
    ISSN: 1436-5057
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Summary Besides the electronic digital computers electronic analog computers and their generalisations to iterativ-analog computers or analog computers controlled by digital computers and finally the connection of analog and digital computers in hybrid computers are of increasing importance especially for those mathematical problems, which do not need the high accuracy of digital computers, whereas the typical possibilities of the analog computers allow a quick survey of the features of the solutions. From these applications we choose a few problems of operations research.
    Notes: Zusammenfassung Neben den elektronischen Digitalrechenanlagen gewinnt heute der elektronische Analogrechner und seine Verallgemeinerung zum iterativen Analogrechner, sowie der durch einen Digitalrechner gesteuerte Analogrechner und schließlich die Verbindung von Analog- und Digitalrechner im Hybridrechner zunehmende Bedeutung. Das gilt vor allem für solche mathematische Problemstellungen, bei denen die große Genauigkeit des Digitalrechners nicht erforderlich ist, andererseits aber die typischen Eigenschaften des Analogrechners einen raschen Überblick über die Eigenschaften der Lösungen ermöglichen. Aus der Fülle derartiger Anwendungen seien im folgenden Probleme der Unternehmungsforschung herausgegriffen.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 58
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 89 (2000), S. 35-53 
    ISSN: 1436-4646
    Keywords: Mathematics Subject Classification (1991): 90C10, 90C11, 90C57
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract. We study a generalization of the vertex packing problem having both binary and bounded continuous variables, called the mixed vertex packing problem (MVPP). The well-known vertex packing model arises as a subproblem or relaxation of many 0-1 integer problems, whereas the mixed vertex packing model arises as a natural counterpart of vertex packing in the context of mixed 0-1 integer programming. We describe strong valid inequalities for the convex hull of solutions to the MVPP and separation algorithms for these inequalities. We give a summary of computational results with a branch-and-cut algorithm for solving the MVPP and using it to solve general mixed-integer problems.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 59
    Electronic Resource
    Electronic Resource
    Springer
    Computing 1 (1966), S. 282-282 
    ISSN: 1436-5057
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 60
    Electronic Resource
    Electronic Resource
    Springer
    Computing 1 (1966), S. 273-280 
    ISSN: 1436-5057
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Summary There exists a general principle for finite matrices, according to which to every matrix norm corresponds an inclusion theorem for eigenvalues. If the norm is the row-sum norm, we have theGershgorin theorem. Another inclusion theorem is used for obtaining bounds for the deviations of the eigenvalues from the diagonal elements, involving the order of the matrix, the maximal modulus of the off-diagonal elements and the distances of the diagonal elements. These bounds yield estimates for theJacobi method for determination of eigenvalues of symmetric matrices.
    Notes: Zusammenfassung Für endliche Matrizen wird ein allgemeines Prinzip gezeigt, das jeder Matrixnorm einen Einschließungssatz für eigenwerte zuordnet. Für die Norm der maximalen Zeilenbetragssumme ergibt sich speziell der Satz vonGerschcorin. Ein anderer Einschließungssatz wird dazu benutzt, für die Abweichungen der Eigenwerte von den Diagonalelementen Schranken aufzustellen, die von der Ordnung der Matrix, dem Maximalbetrag der Nichtdiagonalelemente und den Abständen der Diagonalelemente abhängen. Diese Schranken liefern Fehlerabschätzungen für dasJacobi-Verfahren zur Bestimmung der Eigenwerte symmetrischer Matrizen.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 61
    Electronic Resource
    Electronic Resource
    Springer
    Computing 1 (1966), S. 327-340 
    ISSN: 1436-5057
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung In dieser Arbeit wird die algebraische Struktur von abstrakten Automaten untersucht. Als Hilfsmittel dazu dient die Automorphismengruppe von Automaten, das ist die Gruppe aller Zustandspermutationen, bei welchen die Übergangsfunktion erhalten bleibt. Die Zustandsmenge eines Automaten wird in Äquivalenzklassen von “eng verbundenen” (strongly connected) Teilmengen zerlegt. In der Menge dieser Äquivalenzklassen erklären wir eine Teilordnung, deren minimale Elemente “Quellklassen” (source-classes) genannt werden. Wenn nur eine Quellklasse existiert, dann heißt der Automat zyklisch (Oehmke [3]); wenn jeder Automorphismus alle eng verbundenen Äquivalenzklassen auf sich selbst abbildet, dann nennen wir den Automaten normal. In den bisherigen Arbeiten wurden fast ausschließlich nur eng verbundene Automaten behandelt. Hier hingegen erstrecken sich die Untersuchungen auf zyklische und normale Automaten. Dabei werden auch einige Resultate vonA. Fleck [1] über eng verbundene Automaten verallgemeinert. Gelegentlich beschränken wir uns auf abelsche Automaten.
    Notes: Summary In this paper the structure of automata is investigated using the concept of the automorphism group. The investigations about strongly connected automata are extended to cyclic (Oehmke) and normal automata. The set of states is divided into equivalence classes of strongly connected subsets (SCEC). In the set of all SCEC we explain a partial ordering whose minimal elements are called sourceclasses. If there is only one source-classe, the automaton is called cyclic. If each automorphism maps every SCEC onto itself, then the automaton is said to be normal. We generalize some results ofA. Fleck [1]. In some cases we restrict ourselves to Abelian automata.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 62
    Electronic Resource
    Electronic Resource
    Springer
    Computing 1 (1966), S. 358-367 
    ISSN: 1436-5057
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 63
    ISSN: 1436-5057
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 64
    Electronic Resource
    Electronic Resource
    Springer
    Computing 1 (1966), S. 233-255 
    ISSN: 1436-5057
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Summary As in many branches of science, there has been a change of inner structure taking place in Applied Mathematics in recent times, with a marked turn towards abstraction, exemplified by the wide use of methods of functional analysis. In this summarizing lecture, an attempt is made to demonstrate the useful application of abstract notions in Numerical Mathematics, especially by means of the concept of partial order. This concept is used, for instance, in connection withRiesz' partially ordered Banachspaces, pseudometric spaces, intervals, monotone and positive operators, linear and nonlinear optimization. Applications of monotone operators are given for benting of beams, boundary value problems for linear and nonlinear elliptic differential equations, extrapolation for initial value problems and eigenvalue problems. Emphasis is laid on the interrelation between various problem areas, e.g. between boundary value problems and optimization problems.
    Notes: Zusammenfassung In vielen Wissenschaften, so auch in der Angewandten Mathematik, hat sich in letzter Zeit ein innerer Strukturwandel, insbesondere eine starke Wendung zum Abstrakten hin, vollzogen, welche sich z. B. in der ausgiebigen Verwendung funktionalanalytischer Methoden äußert. In diesem zusammenfassenden Vortrag wird versucht, am Beispiel der Halbordnung die Verwendung und den Nutzen abstrakter Begriffe in der Numerischen Mathematik zu zeigen. Die Halbordnung wird u. a. benutzt bei den Begriffen:Rieszscher Halbordnungs-Banachraum, pseudometrischer Raum, Intervall, monotoner Operator, positiver Operator, lineare und nichtlineare Optimierung. Anwendungen der monotonen Operatoren werden beschrieben bei der Biegegleichung für Träger, bei Randwertaufgaben linearer und nichtlinearer elliptischer Differentialgleichungen, bei der Extrapolation für Anfangswertaufgaben und bei Eigenwertaufgaben. Es werden die Zusammenhänge zwischen verschiedenen Gebieten betont, z. B. zwischen Randwertaufgaben und Optimierungsaufgaben.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 65
    ISSN: 1436-5057
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 66
    Electronic Resource
    Electronic Resource
    Springer
    Computing 1 (1966), S. 309-315 
    ISSN: 1436-5057
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Summary In this paper a universal recurrence formular is given for the calculation of theLegendre-Polynomials an their derivates. The first values for the beginning of the recurrence are calculated. Then there are given some simple formulas for the values of functions with the arguments 0 and 1 at the ends of the considered interval. At last the functional equations are generalized.
    Notes: Zusammenfassung Der vorliegende Beitrag gibt eine universelle Rekursionsformel zur Berechnung derLegendre-Polynome und ihrer Ableitungen an. Die Ausgangswerte der Rekursion werden berechnet. Ferner werden einfache Ausdrücke zur Berechnung der Funktionen an den Intervallenden hergeleitet. In einem letzten Abschnitt werden die bekannten Differentialbeziehungen derLegendre-Polynome verallgemeinert und die Differentialgleichung der (m-1) ten Ableitung des Polynomesn-ten Grades angegeben.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 67
    Electronic Resource
    Electronic Resource
    Springer
    Computing 2 (1967), S. 246-256 
    ISSN: 1436-5057
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Summary We are concerned with the numerical solution of a differential equation which possesses an asymptotic power series. Especially we are interested in arguments from the critical domain. This leads us to the determination of nearly-optimal converging factors. Using the theory of singularVolterra integral equations we obtain for the remainder terms as functions of the converging factors rather good lower and upper bounds. Minimizing these bounds we gain nearly-optimal converging factors, with an error only little greater than the error of the exact optimal converging factors. Moreover we give an estimate of the rapidity of convergence of the approximation sequence. An example shows the effectiveness of our method.
    Notes: Zusammenfassung Wir befassen uns mit der numerischen Lösung einer Differentialgleichung, bei der eine asymptotische Potenzreihe zur Verfügung steht. Besonders interessieren wir uns für Argumente aus dem kritischen Bereich. Dabei tritt das Problem der Bestimmung günstiger Konvergenzfaktoren auf. Es wird für den Formelfehler in Abhängigkeit von den verwendeten Konvergenzfaktoren eine recht genaue Abschätzung sowohl nach oben wie auch nach unten angegeben. Zur Herleitung der Fehlerschranken wird die Theorie der singulärenVolterraschen Integralgleichungen benützt. Die Minimierung der Fehlerschranken liefert dann sehr günstige Konvergenzfaktoren, bei denen der zugehörige Fehler nur wenig über dem Fehler der theoretisch optimalen Lösung liegt. Ferner ergeben sich Aussagen über die Konvergenzgeschwindigkeit der Approximationsfolge. Ein Beispiel zeigt die Wirksamkeit des Verfahrens.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 68
    Electronic Resource
    Electronic Resource
    Springer
    Computing 2 (1967), S. 263-283 
    ISSN: 1436-5057
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Summary Starting from a special formulation of first order functional calculus two procedures are presented producing refutations of inconsistent formulas. Both procedures are based on the notion of interconnecting literals. The first one goes back toHerbrand's Theorem. LetF n be the conjunction ofn copies of the formulaF. An algorithm is introduced to decide whether, for a fixedn, there is an assignment β for the variables ofF n making the formula βF n completely interconnected. By applying this algorithm forn=1,2,... a truth-functionally inconsistent formula of minimal length is constructed. The basic idea of the second procedure is to produce fromF new oneliteral clauses (which are consisten withF). In many cases this proofprocedure, while not complete, is very effective in comparison with other programs; some examples of machine-refutations are given in the appendix. The method may be generalized; in particular it suggests a possibility of man-machine interaction in theorem-proving.
    Notes: Zusammenfassung Ausgehend von einer speziellen Formulierung des Prädikatenkalküls 1. Stufe werden zwei Verfahren entwickelt, welche Widerlegungen inkonsistenter FormelnF liefern. Grundlegend für beide Verfahren ist der Begriff der Verkettung von Literals. Das erste beruht auf demHerbrad-Theorem. SeiF n die Konjunktion vonn Exemplaren der FormelF. Es wird ein Algorithmus angegeben, der entscheidet, ob es bei gegebenemn eine Belegung β der Variablen vonF n gibt, bei welcher die Formel βF n vollständig verkettet ist. Die Anwendung dieses Algorithmus fürn=1,2, ... führt zur Konstruktion einer aussagenlogisch inkonsistenten Formel minimaler Länge. Das zweite Verfahren beruht darauf, daß neue Clausen erzeugt werden, die aus nur einem Literal bestehen (und die mitF konsistent sind). Dieses Verfahren ist nicht vollständig, liefert aber in vielen Fällen schnellere Widerlegungen als andere Methoden; einige Maschinen-Protokolle solcher Widerlegungen sind im Anhang zusammengestellt. Das Verfahren läßt sich verallgemeinern; insbesondere bietet es eine Möglichkeit des Zusammenwirkens von Mensch und Maschine beim Beweisen mathematischer Sätze.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 69
    ISSN: 1436-5057
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 70
    Electronic Resource
    Electronic Resource
    Springer
    Computing 2 (1967), S. 332-335 
    ISSN: 1436-5057
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Summary In this article there will be treated a method to get the involutoric automorphisms of a graph without the execution of any permutation. If a graph has the property that each of it's vertices can be permuted with not more than one other vertex, all automorphisms of the graph are involutoric. In that case the result is the whole group of automorphisms. At the end an ALGOL-procedure is given which computes the involutions if for each vertex the possible image is known.
    Notes: Zusammenfassung In dieser Arbeit wird eine Methode behandelt, die involutorischen Automorphismen von Graphen allein aus den Eigenschaften der Inzidenzmatrix ohne Anwendung von Permutationen aufzustellen. Hat ein Graph die Eigenschaft, daß jeder seiner Punkte mit höchstens einem anderen vertauscht werden kann, so besteht seine Automorphismengruppe aus lauter Involutionen. In diesem Falle erhält man die ganze Automorphismengruppe. Abschließend wird eine ALGOL-Prozedur zur Ermittlung der Involutionen angegeben, wenn für jeden Punkt sein möglicher Bildpunkt bekannt ist.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 71
    Electronic Resource
    Electronic Resource
    Springer
    Computing 2 (1967), S. 353-367 
    ISSN: 1436-5057
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung Die Kongruenzrelationen eines Automaten sind aus verschiedenen Gründen von Interesse. Zum Beispiel bilden sie die Grundlage für Minimisierungsverfahren, oder sie geben die Möglichkeit, einen Automaten in einer Weise zu zerlegen, die technisch bedeutsam ist [Hartmanis et al.]. In der vorliegenden Arbeit haben wir den Zusammenhang zwischen der AutomorphismengruppeG (A) und dem KongruenzenverbandR (A) eines Automaten untersucht. Dieser Zusammenhang beruht hauptsächlich auf einer Galoisverbindung zwischen dem Untergruppenverband vonG (A) und dem VerbandR (A). Dadurch ist eine Teilmenge vonR (A) durch Gruppen zu kennzeichnen. Unterstellt man, daß die Gruppentheorie der triviale Teil der Theorie der Halbgruppen ist, so richtet sich das Interesse auf den verbleibenden Anteil vonR (A), der nicht durchG (A) charakterisiert wird. Ihn in Allgemeinheit zu untersuchen scheint ein aussichtsloses Unterfangen zu sein, weshalb wir uns auf die Klasse der sogenannten rechtsregulären Automaten beschränkt haben. Im letzten Abschnitt wird der theoretische Hintergrund für ein Verfhren entwickelt, das sowohl die Kongruenzen eines Automaten als auch dessen Endomorphismenhalbgruppe systematisch zu erstellen gestattet.
    Notes: Summary The congruence relations of an automaton are of interest for various reasons. For example they are relevant for minimization procedures and they are suitable for decomposing the automaton in a specific way which is of technical importance [Hartmanis et al.]. In this paper we have investigated the interconnection between the automorphism groupG (A) and the latticeR (A) of congruence relations of an automaton. This interconnection is primarily based on a Galois connection between the subgroup lattice ofG (A) and the latticeG (A), which characterizes a subset ofR (A) in terms of groups. Assuming that group theory is the trivial part of the theory of semigroups, the attention is directed to the remainder ofR (A) which is not characterized byG (A) in the way mentioned above. This remainder, however, has not been inspected for the general case, which seems to be a hopeless task, but for the class of so called right regular automata. In the last section some theoretical background for a systematic procedure in obtaining all congruence relations of an automaton as well as its endomorphism semigroup has been developed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 72
    Electronic Resource
    Electronic Resource
    Springer
    Computing 24 (1980), S. 341-347 
    ISSN: 1436-5057
    Keywords: Numerical analysis ; Volterra integral equations of the second kind ; stability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung Ziel dieser Arbeit ist es, die Stabilitätseigenschaften einer Klasse Volterrascher Integralgleichungen zweiter Art zu untersuchen. Unsere Behandlung ist der üblichen Stabilitätsanalyse ähnlich, in der die Kernfunktionen zu einer im voraus beschränkten Klasse von Testfunktionen gehören. Wir haben die Klasse der “endlich zerlegbaren” Kerne betrachtet. Stabilitätsbedingungen werden abgeleitet und verglichen mit den Bedingungen für die einfache Testgleichung. Es zeigt sich, daß die neuen Kriteria einschränkender sind als die konventionellen Bedingungen. Der praktische Wert wird getestet durch numerische Experimente mit der Trapezregel.
    Notes: Abstract The purpose of this paper is to analyse the stability properties of a class of multistep methods for second kind Volterra integral equations. Our approach follows the usual analysis in which the kernel function is a priori restricted to a special class of test functions. We consider the class of finitely decomposable kernels. Stability conditions will be derived and compared with those obtained with the simple test equation. It turns out that the new criteria are more severe than the conventional conditions. The practical value is tested by numerical experiments with the trapezoidal rule.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 73
    ISSN: 1436-5057
    Keywords: 65 J ; 65 H
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Summary A generalization of the concept of a divided difference operator introduced by J. W. Schmidt is derived. The inclusion of solutions by certain Regula-falsi-methods realized by a well known approximation of the Jacobian matrix, which is no divided difference operator in the sense of Schmidt but a realization of this generalization, is proved.
    Notes: Zusammenfassung Durch Verallgemeinerung des von J. W. Schmidt eingeführten Steigungsbegriffes gelingt es, bei Durchführung gewisser Verfahren vom Regula-falsi-Typ mit einer naheliegenden und häufig verwendeten Approximation der Funktionalmatrix, die keine Steigung im herkömmlichen Sinne darstellt, jedoch eine Realisierung der oben genannten Verallgemeinerung liefert, Einschließungsaussagen für Lösungen von Operatorgleichungen nachzuweisen.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 74
    Electronic Resource
    Electronic Resource
    Springer
    Computing 26 (1981), S. 57-66 
    ISSN: 1436-5057
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Abstract An algorithm is proposed for computation of the exponential of a matrixX which uses the well known continued fraction expansion of tanhX. ForX essentially-nonnegative the following is proved: In interval arithmetic the algorithm is feasible, numerically convergent and bound conserving; after possibly a few initial steps it gives alternatively lower and upper bounds to the exact result.
    Notes: Zusammenfassung Es wird ein Algorithmus zur Berechnung der Exponentialfunktion von MatrizenX vorgeschlagen, der die Kettenbruch-Entwicklung von tanhX benutzt. IstX wesentlich-nichtnegativ, dann gilt: Der Algorithmus ist in Intervall-Arithmetik durchführbar, numerisch konvergent und schrankentreu; von einem Index an liefert er alternierend untere und obere Schranken für das exakte Ergebnis.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 75
    Electronic Resource
    Electronic Resource
    Springer
    Computing 26 (1981), S. 45-56 
    ISSN: 1436-5057
    Keywords: Order-convex operator ; Banach space ; Existence ; Convergence ; Operator equation ; partially ordered topological linear space ; 65J15 ; 47H17 ; 47H07
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung SeiF:X→Y ein ordnungskonvexer Operator, woX, Y halbgeordnete Banachräume sind. Es werden zwei verwandte Verfahren zur Lösung der GleichungF(x)=0 diskutiert, von denen eines schon von Pasquali beschrieben worden ist (s. [2]), das andere von Wolfe [12]. Existenz- und Konvergenzsätze für diese Verfahren sind dargestellt und mit Hilfe von Beispielen illustriert. Ferner liegen einige Bemerkungen über ein Verfahren von Traub vor, das auch schon von Wolfe diskutiert worden ist [12].
    Notes: Abstract LetF:X→Y be an order-convex operator, whereX, Y are partially ordered Banach spaces. Two related methods for the solution ofF(x)=0 are discussed, one of which has been studied by Pasquali (see [2]) and the other by Wolfe [12]. Existence-convergence theorems for the methods are given, and these are illustrated with the aid of example. Some remarks are also made on a method due to Traub [7] which has also been discussed by Wolfe [12].
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 76
    Electronic Resource
    Electronic Resource
    Springer
    Computing 26 (1981), S. 19-31 
    ISSN: 1436-5057
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung Gegeben sei ein Pseudo-Zufallszahlen-Generator, der gleichverteilte StichprobenU aus dem Intervall (0, 1) liefert, und eine statistische Verteilung, beschrieben durch ihre VerteilungsfunktionF(x). Dann erzeugt die InversionsmethodeX←F −1(U) Stichproben vonF(x). Ein Verfahren wird entwickelt, das “Guide”-Tafeln erstellt, mit dem Ziel, diese Inversion zu ermöglichen, so daß das Verfahren für beliebigeF(x) effizient wird. Für diskrete Verteilungen sind diese Tafeln klein und leicht zu erstellen, und der entstehende Stichproben-Algorithmus kann mit bekannten allgemeinen Verfahren gut konkurrieren. Stetige Verteilungen erfordern längere Vorbereitungszeiten und mehr Speicherplatz für die Tafeln. Diese werden mit Hilfe gegebener Wahrscheinlichkeitsdichtenf(x) vorbereitet. Die Methode ist anwendbar auf “vernünftige”f(x), einschließlich der normalerweise in der Statistik vorkommenden Fälle. Aufgrund der angeführten Rechenerfahrung mit Poisson-, Normal-, Gamma- und Cauchy-Verteilungen zeigt sich, daß unser allgemeines Verfahren fast so schnell ist, wie die besten bekannten Methoden, die speziell auf diese Verteilungen zugeschnitten wurden.
    Notes: Abstract Given a basic pseudo-random number generator which returns uniformly distributed samplesU from the interval (0, 1) and a statistical distribution as defined by its distribution functionF(x). Then the inversion methodX←F −1 (U) produces samples fromF(x). A procedure is developed which prepares “guide tables” in order to facilitate this inversion so that sampling becomes efficient for arbitraryF(x). For discrete distributions these tables are small and easy to set up, and the resulting sampling algorithm compares well with known general methods. Continuous distributions require longer set-up times and more space for tables. These are prepared using given probability densitiesf(x). The method can cope with “reasonable”f(x) including most cases which are commonly encountered in statistics. The reported computational experience, on Poisson, Normal, Gamma and Cauchy distributions, indicates that our general routine is almost as fast as the best known sampling algorithms which were specially designed for these distributions.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 77
    Electronic Resource
    Electronic Resource
    Springer
    Computing 26 (1981), S. 67-71 
    ISSN: 1436-5057
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung Die Berechnung von beliebigen Funktionen dreieckiger Matrizen ist rekursiveweise ermöglicht mittels einfacher Eigenschaften, dagelegt in diesem Bericht.
    Notes: Abstract Any function of a triangular matrix can be recursively calculated on the basis of simple properties stated in this paper.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 78
    Electronic Resource
    Electronic Resource
    Springer
    Computing 26 (1981), S. 73-77 
    ISSN: 1436-5057
    Keywords: Cauchy type singular integral equations ; natural interpolation formulae ; Gauss-Chebyshev quadrature rule ; Nyström (quadrature) method for integral equations ; direct numerical solution of Cauchy type singular integral equations ; Primary: 65R20 ; Secondary: 45E05, 45L10, 65D05
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung Eine singuläre Integralgleichung erster Art vom Cauchy-Typ kann entweder direkt, mittels einer Gaußschen numerischen Integrationsformel, oder durch Reduktion auf eine äquivalente Fredholmsche Integralgleichung zweiter Art, wo die Nyström-Methode anwendbar ist, gelöst werden. In dieser Arbeit wird bewiesen, daß unter geeigneten und sinnvollen Bedingungen die Ausdrücke der unbekannten Funktion der Integralgleichung, die einerseits bei den natürlichen Integrationsformeln der direkten Methode und anderseits bei der Nyström-Methode entstehen, im ganzen Integrationsintervall gleich sind.
    Notes: Abstract A Cauchy type singular integral equation of the first kind can be numerically solved either directly, through the use of a Gaussian numerical integration rule, or by reduction to an equivalent Fredholm integral equation of the second kind, where the Nyström method is applicable. In this note it is proved that under appropriate but reasonable conditions the expressions of the unknown function of the integral equation, resulting from the natural interpolation formulae of the direct method, as well as of the Nyström method, are identical along the whole integration interval.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 79
    Electronic Resource
    Electronic Resource
    Springer
    Computing 26 (1981), S. 79-82 
    ISSN: 1436-5057
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung Es werden notwendige und hinreichende Bedingungen für das Problem der linearen Optimierung mit Intervallkoeffizienten angegeben, bei denen jedes Problem der linearen Optimierung, dessen Koeffizienten in gegebenen Intervallen fixiert werden, eine optimale Lösung besitzt.
    Notes: Abstract Necessary and sufficient conditions for a linear programming problem whose parameters (both in constraints and in the objective function) are prescribed by intervals are given under which any linear programming problem with parameters being fixed in these intervals has a finite optimum.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 80
    Electronic Resource
    Electronic Resource
    Springer
    Computing 26 (1981), S. 87-89 
    ISSN: 1436-5057
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung Tseitin [3] und Galil [1] haben gezeigt, daß es in der Aussagenlogik für unendlich vielen KlausenmengenS(n) der Längen gibt, so daß jeder reguläre Resolutionsbeweis fürS(n) mindestens 2 cn (für einec〉0) verschiedene Klausen enthält. Wir geben hier einen einfacheren Beweis für die viel schwächere aber dennoch nichtpolynomiale Schranke 2 clog 2 n an.
    Notes: Abstract Tseitin [3] and Galil [1] have proven that for infinitely manyn there is a set of clausesS(n) of the propositional calculus of lengthn such that any regular resolution proof ofS(n) produces at least 2 cn distinct new clauses for somec〉0. We show that it is possible to obtain a much weaker but still non-polynomial bound of 2 clog 2 n by a simpler argument.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 81
    Electronic Resource
    Electronic Resource
    Springer
    Computing 26 (1981), S. 83-86 
    ISSN: 1436-5057
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung Wir wenden den Satz, daß für eine Segmentfunktionf, deren SegmentableitungD(f) auf dem Segment [0, 1] von oben beschränkt ist, der Hausdorff-Abstand zwischenD(f) und der Ableitung eines linearen Operators durch den Modul derH-Stetigkeit vonD(f) und Konstante nach oben beschränkt ist, an auf Bernstein-Polynome und Mirakyan-Szász-Operatoren.
    Notes: Abstract Given a segment functionf, whose segment-derivative is bounded from above on the segment [0, 1] we applicate the theorem, that the Hausdorff distance betweenD(f) and the derivative of a linear operator is bounded from above by the modulus of H-continuity ofD(f) and some constants, to Bernstein polynomials and Mirakyan-Szász-operators.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 82
    Electronic Resource
    Electronic Resource
    Springer
    Computing 26 (1981), S. 91-105 
    ISSN: 1436-5057
    Keywords: 65N20 ; Adaptive mesh refinement ; multigrid methods ; finite element methods
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung Das Unterprogramm PLTMG ist ein FORTRAN-Programm zur Lösung selbstadjungierter elliptischer Randwertprobleme für beliebige Bereiche desR 2. Es basiert auf einer stückweise-linearen Finite-Element-Methode, einer adaptiven Gitterverfeinerungsmethode und einer mehrstufigen iterativen Methode zur Lösung des resultierenden Systems linearer Gleichungen. In dieser Arbeit wird die Methode beschrieben, und einige numerische Ergebnisse und Vergleiche werden dargelegt.
    Notes: Abstract Subroutine PLTMG is a Fortran program for solving self-adjoint elliptic boundary value problems in general regions ofR 2. It is based on a piecewise linear triangle finite element method, an adaptive grid refinement procedure, and a multi-level iterative method to solve the resulting sets of linear equations. In this work we describe the method and present some numerical results and comparisons.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 83
    ISSN: 1436-5057
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung Die Benutzung algebraischer Eigenwerte zur näherungsweisen Berechnung der Eigenwerte von Sturm-Liouville-Operatoren ist bekanntlich nur für die Grundschwingung und einige weitere Harmonische zufriedenstellend. In dieser Arbeit zeigen wir, wie man den asymptotischen Fehler, der bei verwandten aber einfachen Sturm-Liouville-Operatoren auftritt, dazu benutzen kann, um gewisse Klassen algebraischer Eigenwerte so zu korrigieren, daß die gleichmäßig gute Approximationen liefern.
    Notes: Abstract The use of algebraic eigenvalues to approximate the eigenvalues of Sturm-Liouville operators is known to be satisfactory only when approximations to the fundamental and the first few harmonics are required. In this paper, we show how the asymptotic error associated with related but simpler Sturm-Liouville operators can be used to correct certain classes of algebraic eigenvalues to yield uniformly valid approximations.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 84
    Electronic Resource
    Electronic Resource
    Springer
    Computing 26 (1981), S. 107-121 
    ISSN: 1436-5057
    Keywords: Primary: 65 H ; Secondary: 47 H ; Turning points ; Newton-like methods ; continuation methods ; local convergence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung Die RaumkurveL werde implizit durch das nichtlineare (n, n+1)-SystemH(u)=0 definiert. Es wird ein neues direktes Newton-ähnliches Verfahren zur Bestimmung der Rückkehrpunkte vonL beschrieben, das pro Schritt lediglich die Berechnung einer Jacobimatrix und 5 Funktionswerten vonH erfordert. Außerdem ist pro Schritt ein lineares Gleichungssystem der Dimensionn+1 mit 4 verschiedenen rechten Seiten zu lösen. Unter passenden voraussetzungen wird die lokale undQ-quadratische Konvergenz des Verfahrens bewiesen, sofern eine gewisse Diskretisierungsschrittweise geeignet gewählt wird. Zwei numerische Beispiele bestätigen die theoretischen Resultate.
    Notes: Abstract Let the space curveL be defined implicitly by the (n, n+1) nonlinear systemH(u)=0. A new direct Newton-like method for computing turning points ofL is described that requires per step only the evaluation of one Jacobian and 5 function values ofH. Moreover, a linear system of dimensionn+1 with 4 different right hand sides has to be solved per step. Under suitable conditions the method is shown to converge locally withQ-order two if a certain discretization stepsize is appropriately chosen. Two numerical examples confirm the theoretical results.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 85
    Electronic Resource
    Electronic Resource
    Springer
    Computing 26 (1981), S. 155-166 
    ISSN: 1436-5057
    Keywords: decomposable searching problem ; dynamization ; merging ; quad-trees ; k-d trees ; halfspaces ; maximal elements
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung Wir definieren zwei Klassen zerlegbarer Suchprobleme und untersuchen, wie man diese Probleme effizient dynamisch lösen könnte. Für die erste Klasse (DD) zeigen wir, daß man sowohl das Einfügen als auch das Streichen von einzelnen Elementen im Zeitmittel effizient durchführen kann. Für die zweite Klasse (MD) zeigen wir zudem, daß man mit der Benützung einer schnellen Mischungsprozedur die Effizienz noch um ein wenig verbessern kann. Alss Anwendungen zeigen wir z. B. die effiziente Dynamisierung von Quadbäumen und vom gemeinsamen Durchschnitt endlich vieler Halbebenen in der Ebene.
    Notes: Abstract We define two classes of decomposable searching problems and consider ways of efficiently dynamizing them. For the first class, DD, we show that both insertions and deletions can be processed efficiently. For the second class, MD, we exploit a merge technique to obtain better insertion times. We also give a number of examples of problems to which the methods apply, including the dynamic maintenance of quadtrees and of the common intersection of finitely many halfspaces in the plane.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 86
    Electronic Resource
    Electronic Resource
    Springer
    Computing 4 (1969), S. 24-29 
    ISSN: 1436-5057
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung Die vorliegende Arbeit bringt einige ergänzende Resultate über ein in [4] betrachtetes Wartesystem. Die in [4] entwickelten numerischen Methoden zur Berechnung von Gleichgewichtswahrscheinlichkeiten werden diskutiert.
    Notes: Summary In an earlier paper [4] a certain service system has been investigated. The present paper adds some further results and discusses the numerical methods developed in [4] for the calculation of equilibrium probabilities.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 87
    Electronic Resource
    Electronic Resource
    Springer
    Computing 4 (1969), S. 75-75 
    ISSN: 1436-5057
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 88
    ISSN: 1436-5057
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 89
    Electronic Resource
    Electronic Resource
    Springer
    Computing 4 (1969), S. 92-92 
    ISSN: 1436-5057
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 90
    ISSN: 1436-5057
    Keywords: 90C30 ; 65K05 ; Nonlinear programming algorithms ; penalty algorithms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung Diese Arbeit beschreibt einen Algorithmus zur Minimierung einer nichtlinearen Funktion mit nichtlinearen Ungleichungen und Gleichungen als Nebenbedingungen. Die vorgeschlagene Methode hat die Eigenschaft, daß sie unter schwachen Voraussetzungen gegen einen Kuhn-Tucker-Punkt des betrachteten Optimierungsproblems konvergiert und unter stärkeren Voraussetzungen eine quadratische Konvergenzgeschwindigkeit aufweist. Ähnlich wie eine vor kurzem von Rosen vorgeschlagene Methode benutzt der Algorithmus eine Straffunktion, um einen Punkt in der Nähe der optimalen Lösung zu berechnen und schaltet dann auf Robinsons Methode um. Die neue Methode hat gegenüber dem Verfahren von Rosen zwei neue Eigenschaften. Erstens wird der richtige Wert des Parameters in der Straffunktion automatisch gefunden. Zweitens enthalten die mit der Methode von Robinson gelösten Teilprobleme nur lineare Gleichungen als Nebenbedingungen. Die Teilprobleme können daher besonders leicht gelöst werden. Vorläufige numerische Ergebnisse werden berichtet.
    Notes: Abstract This paper presents an algorithm for the minimization of a nonlinear objective function subject to nonlinear inequality and equality constraints. The proposed method has the two distinguishing properties that, under weak assumptions, it converges to a Kuhn-Tucker point for the problem and under somewhat stronger assumptions, the rate of convergence is quadratic. The method is similar to a recent method proposed by Rosen in that it begins by using a penalty function approach to generate a point in a neighborhood of the optimum and then switches to Robinson's method. The new method has two new features not shared by Rosen's method. First, a correct choice of penalty function parameters is constructed automatically, thus guaranteeing global convergence to a stationary point. Second, the linearly constrained subproblems solved by the Robinson method normally contain linear inequality constraints while for the method presented here, only linear equality constraints are required. That is, in a certain sense, the new method “knows” which of the linear inequality constraints will be active in the subproblems. The subproblems may thus be solved in an especially efficient manner. Preliminary computational results are presented.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 91
    Electronic Resource
    Electronic Resource
    Springer
    Computing 26 (1981), S. 209-225 
    ISSN: 1436-5057
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung Es wird gezeigt, wie das probabilistische Konzept der Stoppzeit eines Zufallsprozesses für eine iterative Methode zur Lösung eines Systems linearer Gleichungen herangezogen werden kann. Alle bekannten iterativen Näherungsmethoden zur Lösung linearer Gleichungssysteme, wie z. B. die Blockmethoden nach Jakobi und Gauss-Seidel und Überrelaxationsmethoden, entsprechen verschieden gewählten Stoppzeiten. Das probabilistische Verfahren bietet die Möglichkeit, Lösungstechniken für die spezielle Struktur des Problems zu adaptieren. Darüber hinaus führen die vorgeschlagenen Methoden zu einer schnelleren Konvergenz.
    Notes: Abstract In this paper it is demonstrated how the probabilistic concept of a stopping time in a random process may be used to generate an iterative method for solving a system of linear equations. Actually all known iterative approximation methods for solving linear equations are generated by various choices of a stopping time e. g. the point and block Jacobi methods, the point and block Gauss-Seidel Methods and overrelaxation methods are covered. The probabilistic approach offers—in a natural way—the possibility of adapting the solution technique to the special structure of the problem. Moreover, posterior bounds for the solution are constructed, which lead to faster convergence of the approximations than with usual prior bounds.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 92
    Electronic Resource
    Electronic Resource
    Springer
    Computing 26 (1981), S. 227-237 
    ISSN: 1436-5057
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung In dieser Arbeit werden mehrere systematische Möglichkeiten angegeben, die es erlauben, bei der Verwendung der intervallmäßigen Auswertung der Ableitung in Iterationsverfahren gewisse Intervalle durch reelle Zahlen zu ersetzen. Dadurch wird im allgemeinen die Konvergenz beschleunigt. Die gleiche Problemstellung wurde bereits von einem anderen Ausgangspunkt ausgehend in [5] betrachtet.
    Notes: Abstract We discuss several systematic possibilities for removing certain intervals when using an interval expression of the derivative in iterative methods. In general, the speed of convergence is accelerated in this way. Starting from a different point of view the same problem has been treated recently in [5].
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 93
    Electronic Resource
    Electronic Resource
    Springer
    Computing 26 (1981), S. 239-246 
    ISSN: 1436-5057
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung Es werden charakteristische Eigenschaften solcher Approximationen gegeben. Ein Algorithmus, der gute, aber nicht unbedingt beste Approximationen liefert, wird diskutiert.
    Notes: Abstract Characteristic properties of such approximations are given. An algorithm providing good, but not necessarily best, approximations is also discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 94
    Electronic Resource
    Electronic Resource
    Springer
    Computing 26 (1981), S. 247-256 
    ISSN: 1436-5057
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung In dieser Arbeit werden sämtliche Nyström-Methoden fünfter Ordnung füry″=f(x, y) angegeben, welche vier Funktionsauswertungen pro Schritt benötigen. Es wird gezeigt, daß sich darunter nur eine einzige mit einem nichtleeren Periodizitätsintervall befindet.
    Notes: Abstract In this paper all fifth order Nyström methods fory″=f(x, y) based on four evaluations off are presented. Furthermore, we prove that out of these methods there is only one with a non-vanishing interval of periodicity.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 95
    Electronic Resource
    Electronic Resource
    Springer
    Computing 26 (1981), S. 271-274 
    ISSN: 1436-5057
    Keywords: 65 G 10 ; Differentiation ; interval valued functions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Abstract This paper is concerned with relations between several versions of differentiation of interval valued functions.
    Notes: Zusammenfassung Es werden Beziehungen zwischen verschiedenen Ableitungsbegriffen für intervallwertige Funktionen angegeben.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 96
    Electronic Resource
    Electronic Resource
    Springer
    Computing 26 (1981), S. 315-326 
    ISSN: 1436-5057
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung Es wird eine einfache, aber wirkungsvolle Methode zur exakten Lösung eines nichtlinearen Gleichungssystems, dessen Funktionalmatrix in der Lösung singulär ist, vorgestellt. Dies wird durch eine Vergrößerung des Gleichungssystems zu einem höherdimensionalen Gleichungssystem, dessen entsprechende Lösung isoliert ist, erreicht. Diese Lösung kann daher z. B. mit dem Newton-Verfahren, das lokal mindestens quadratisch konvergent und selbstkorrigierend ist, mit großer Genauigkeit bestimmt werden.
    Notes: Abstract A simple but efficient method to obtain accurate solutions of a system of nonlinear equations with a singular Jacobian at the solution is presented. This is achieved by enlarging the system to a higher dimensional one whose solution in question is isolated. Thus it can be computed e. g. by Newton's method, which is locally at least quadratically convergent and selfcorrecting, so that high accuracy is attainable.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 97
    ISSN: 1436-5057
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung In numerischen Rechnungen treten neben den ganzen Zahlen häufig auch reelle und komplexe Zahlen, reelle und komplexe Intervalle sowie Vektoren und Matrizen über diesen Mengen auf. In der vorliegenden Arbeit erweitern wir die ProgrammierspracheFORTRAN so, daß Ausdrücke mit Operanden und Operatoren für all diese Typen (Datenmengen) akzeptiert werden. Wir beginnen mit einer kurzen Zusammenstellung dieser Räume und der arithmetischen Verknüpfungen in den Teilmengen, welche auf einem Rechner darstellbar sind. Es folgt dann eine allgemeine Beschreibung der Spracherweiterung sowie der neuen Standardfunktionen und Standardformelfunktionen für die zusätzlichen Datentypen. Im zweiten Teil der Arbeit geben wir dann die vollständige Syntax für die erweiterte Sprache in Form von leicht lesbaren Syntaxdiagrammen an. Wir erläutern auch die Semantik der Spracherweiterung.
    Notes: Abstract In addition to the integers, the real and complex numbers, the real segments (intervals) and complex segments as well as vectors and matrices over all of these comprise the fundamental data types in computation. We extendFORTRAN so that it accepts operands and operators for all of these types as primitives in expressions. We briefly review the spaces corresponding to these data types and the definitions of the arithmetic operations in their computer representable subsets. Then we give a general description of the language extension including the additional basic external functions and intrinsic functions for the new data types. Following this we give the syntax for the extended language in the form of easily traceable syntax diagrams. Comments on the semantics are also included.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 98
    Electronic Resource
    Electronic Resource
    Springer
    Computing 26 (1981), S. 327-332 
    ISSN: 1436-5057
    Keywords: 65 N 20 (Numerical solution of nonlinear boundary value problems)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Abstract For nonlinear SOR-methods (Newton-SOR-methods) we discuss the problem how to get asymptotic optimal relaxation parameters ω(v). Here the matrix of the linear system at each step of iteration has not to be consistently ordered, we only assume symmetry and definitness. Our parameters are easy to compute and fixed for all steps. As an example nonlinear elliptic differential equations and their numerical solution by the finite element method or classical difference approximation are considered.
    Notes: Zusammenfassung Für nichtlineare SOR-Verfahren (Newton-SOR-Verfahren) wird ein einfaches Verfahren zur Berechnung asymptotisch optimaler Relaxationsparameter ω(v) erörtert. Hierbei muß die Matrix des in jedem Iterationsschritt auftretenden linearen Gleichungssystems nicht notwendig konsistent geordnet sein, wir setzen nur Symmetrie und Definitheit voraus. Es zeigt sich, daß die Parameter unabhängig von der jeweiligen Iterationsstufe ν gewählt werden können. Ihre Berechnung wird im Zusammenhang mit der numerischen Lösung nichtlinearer elliptischer Differentialgleichungen vermittels der Methode der finiten Elemente oder der klassischen Differentenapproximation diskutiert.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 99
    Electronic Resource
    Electronic Resource
    Springer
    Computing 26 (1981), S. 333-342 
    ISSN: 1436-5057
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung Für Folgen aus einem iterativen Näherungsverfahren, die einem mit Hilfe von Potenzfunktionen beschreibbaren System von Ungleichungen genügen, wird gezeigt, daß ihre R-Ordnung mindestens gleich dem Spektralradius der Matrix aus den Exponenten ist, sofern ein zum Spektralradius gehörender Eigenvektor mit ausschließlich positiven Komponenten existiert.
    Notes: Abstract The R-order of sequences, coupled by a system (1) of difference inequalities, is shown to be at least equal to the spectral radius of the matrix of the exponents if a positive eigenvector belonging to the spectral radius exists.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 100
    Electronic Resource
    Electronic Resource
    Springer
    Computing 26 (1981), S. 355-360 
    ISSN: 1436-5057
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung Es wird gezeigt, daß die Sicherheit eines Programmes für gewöhnliche Differentialgleichungen durch einen einfachen Trick wesentlich erhöht werden kann. Mit Hilfe dieser Idee und einer A-stabilen Rosenbrock-Formel haben wir ein kleines Programm geschrieben, welches gute numerische Resultate liefert.
    Notes: Abstract This note points out that the reliability of step-by-step integrators for ordinary differential equations can be increased considerably by a simple trick. We incorporated this idea into a program based on an A-stable Rosenbrock formula. This program comprises about 100 statements only and gives good numerical results.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...