ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
Filter
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Zeitschrift für angewandte Mathematik und Physik 34 (1983), S. 728-745 
    ISSN: 1420-9039
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Physics
    Description / Table of Contents: Zusammenfassung Für gewisse monotone OperatorenF andG untersuchen wir positive Lösungen des nichtlinearen EigenwertproblemsF(u)=λG(u). Insbesondere betrachten wir nichtlineare elliptische Differentialgleichungen zweiter Ordnung und wählenF(u)=−divA(x, gradu)+b(x,u) sowieG(u)=g(x,u). Man erhält positive Lösungen durch das Picard-Iterationsverfahrenu 0=0 undF(u n+1)=λG(u n ).Um die Konvergenz der Folgeu n nachzuweisen, benötigt man Vergleichsprinzipien fürF. Dann gestattet das Iterationsschema sogar a-priori Abschätzungen und Verzweigungsaussagen für die zulässigen Eigenwertparameterλ.
    Notes: Summary We study positive solutions of the nonlinear eigenvalue problemF(u)=λG(u) with some monotone operatorsF andG. In particular, we consider the case of nonlinear elliptic differential equations of second order and chooseF(u)=−divA(x, gradu)+b(x,u) and G(u)=g (x,u). Positive solutions are obtained by the Picard iterationsu 0=0 andF(u n+1)=λG(u n ).In order to get convergence of the sequenceu n ,one has to study some comparison principles for the operatorF. Finally, the Picard iteration scheme allows a-priori estimates and bifurcation results for the admissible eigenvalue parameterλ.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Zeitschrift für angewandte Mathematik und Physik 36 (1985), S. 499-507 
    ISSN: 1420-9039
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Physics
    Description / Table of Contents: Zusammenfassung Wir betrachten die nichtlineare Diffusionsgleichungu t −a(x, u x ) x +b(x, u)=λg(x, u) mit Randbedingungen $$u\left( {0, x} \right) = \mathop u\limits_ - \left( x \right)$$ undu (t, 0)=u (t, 1)=0. Dabei sinda, b, undg monoton wachsende Funktionen bzgl. des zweiten Argumentes. Das zugehörige stationäre Problem hat genau dann eine positive Lösung, fallsλ∈ (0,λ *) oderλ∈(0,λ *]. Der Endpunktλ * kann durch $$\begin{gathered} \lambda * \leqq \sup \mu _1 \left\{ u \right\} \hfill \\ u \hfill \\ \end{gathered} $$ abgeschätzt werden, wobeiμ 1 u den ersten Eigenwert des an der Stelleu linearisierten stationären Problems bezeichnet. Die minimale positive stationäre Lösung ist stabil bzgl. der obigen nichtlinearen parabolischen Gleichung.
    Notes: Abstract We consider the nonlinear diffusion equationu t −a(x, u x x )+b(x, u)=λg(x, u) with initial boundary conditions $$u\left( {0, x} \right) = \mathop u\limits_ - \left( x \right)$$ andu(t, 0)=u(t, 1)=0. Here,a, b, andg denote some real functions which are monotonically increasing with respect to the second variable. Then, the corresponding stationary problem has a positive solution if and only ifλ∈(0,λ *) orλ∈(0,λ *]. The endpointλ * can be estimated by $$\begin{gathered} \lambda * \leqq \sup \mu _1 \left\{ u \right\} \hfill \\ u \hfill \\ \end{gathered} $$ , whereμ 1 u denotes the first eigenvalue of the stationary problem linearized at the “point”u. The minimal positive steady state solutions are stable with respect to the nonlinear parabolic equation.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Manuscripta mathematica 38 (1982), S. 163-174 
    ISSN: 1432-1785
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract Suppose that L is a linear, closed operator and A is a hemi-continuous, (cyclically) monotone operator with D(A) ⊃ D(L). Both operators are defined in a Hilbert space. Then, it can be shown that A+L*L is maximal (cyclically) monotone, though A is not necessarily maximal. However, if A has the property (Au-Av, u-v)≥ge2‖L(u-v)‖2 then even A is maximal. Using this abstract result and the theory of sesquilinear forms, it requires only some technical calculation to show that the generalized Hartree operator $$F(u) = - a^2 \Delta u + (q(x) + b)u(x) + u(x)\int\limits_{\mathbb{R}^3 } {\frac{{u^2 }}{{|x - y|}}d^3 y} $$ is maximal (cyclical) monotone in the space L2 (ℝ3).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Manuscripta mathematica 28 (1979), S. 305-316 
    ISSN: 1432-1785
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract In a Hilbert space H, we consider operators of type A=L*ϕ·L, where L is a closed, linear operator and ϕ is a maximal cyclically monotone, coercive operator. The operators ϕ, L, L* and their inverses are not necessarily everywhere defined. Our principle result is a nonlinear extension of an earlier theorem of v. Neumann for A=L*L.Theorem: Suppose that either (L*)−1 is bounded or that both L−1 is bounded and, D(ϕ) υ N (L*). The L*ϕ·L, is maximal cyclically monotone. Maximality of sums $$\mathop \Sigma \limits_{i = O}^n (L*)^{i_\Phi } _i {}^ \circ L^i $$ is also considered, and the theory is applied to concrete differential operators of the form $$\mathop \Sigma \limits_{i = 0}^n ( - 1)^i f_i (u^{[i]} )^{[i]} $$ , with monotone functions f1 and various boundary conditions.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 10 (1988), S. 477-485 
    ISSN: 0170-4214
    Keywords: Mathematics and Statistics ; Applied Mathematics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Notes: We consider the non-linear evolution equation μdu/dt+Bu+n(u)L(u)=h, where n(u) is a functional, and introduce assumptions which allow its explicit solution. Several concrete applications of our procedure are given.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Publication Date: 1982-07-01
    Print ISSN: 0362-546X
    Electronic ISSN: 1873-5215
    Topics: Mathematics
    Published by Elsevier
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Publication Date: 1982-06-01
    Print ISSN: 0362-546X
    Electronic ISSN: 1873-5215
    Topics: Mathematics
    Published by Elsevier
    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...