Abstract
Demonstrates how a proper rational fraction approximation to the singular eigenfunction of the neutron transport theory can be constructed based on the properties of generalised functions and singular integral equations. The parameters of the approximant are determined by a proper use of the orthogonality integrals satisfied by the Case eigenfunctions. This ensures the convergence of the approximant to its exact singular distributional form. Use of Lebesgue integrable spaces made in the analysis leads to a new possibility of approximating functions in Lp, 1<p< infinity , and also of finding approximate solutions of singular integral equations.