This volume presents the proceedings of the 11th Conference on Problems and Methods in Mathematical Physics (11th TMP), held in Chemnitz, March 25-28, 1999. The conference was dedicated to the memory of Siegfried Prössdorf, who made important contributions to the theory and numerical analysis of operator equations and their applications in mathematical physics and mechanics. The main part of the book comprises original research papers. The topics are ranging from integral and pseudodifferential equations, boundary value problems, operator theory, boundary element and wavelet methods, approximation theory and inverse problems to various concrete problems and applications in physics and engineering, and reflect Prössdorf's broad spectrum of research activities. The volume also contains articles describing the life and mathematical achievements of Siegfried Prössdorf and includes a list of his publications. The book is addressed to a wide audience in the mathematical and engineering sciences.

Inhalt
Obituary.- In memory of Siegfried Prößdorf.- Siegfried Prößdorf A short review of his scientific career.- On the theory of a singular Vekua system.- Singular integral operators with complex conjugation from the viewpoint of pseudodifferential operators.- Biorthogonal wavelet approximation methods for the heat equation.- Orientable and nonorientable Riemann-Hilbert problems.- Diffraction in periodic structures and optimal design of binary gratings. Part II: Gradient formulas for TM polarization.- A connection between the determinant and characteristic numbers of an operator pencil.- Random walk models approximating symmetric space-fractional diffusion processes.- On qualocation and collocation methods for singular integral equations with piecewise continuous coefficients, using continuous splines on quasi-uniform meshes.- Toeplitz operators and the modelling of oscillating discontinuities with the help of Blaschke products.- Towards H-matrix approximation of linear complexity.- Wavelet Galerkin schemes for 2D-BEM.- On the stability of collocation methods for Cauchy singular integral equations on an interval.- On a new approach for solving Dirac equations with some potentials and Maxwell's system in homogeneous media.- Revisiting a quadrature method for CSIE with weakly singular perturbation kernel.- Fourier projections in weighted L?-spaces.- Maximal Banach algebra in spaces of multipliers between Bessel potential spaces.- Mixed type direct and inverse scattering problems.- On an inverse problem in groundwater filtration and its regularization by the conjugate gradient method.- On a constructive representation of an orthogonal trigonometric Schauder basis for C2?.- Discretization methods for the Lavrent'ev regularization.- On a hierarchical three-pointbasis in the space of piecewise linear functions over smooth surfaces.- Algebras of approximation sequences: Fractality.- Fast solvers of generalized airfoil equation of index 1.- On plane potential flow past a porous circular cylinder.