IMA Journal of Applied Mathematics Advance Access published online on July 26, 2007
IMA Journal of Applied Mathematics, doi:10.1093/imamat/hxm021
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Method of integral equations for systems of difference equations in diffraction theory

Department of Mathematics, Louisiana State University, Baton Rouge, LA 70803, USA

Department of Mathematics, Gubkin Russian State University of Oil and Gas, Moscow 119991, Russia
Email: antipov{at}math.lsu.edu
Email: v_silvestrov{at}mail.ru
Received on April 4, 2006; Accepted on May 8, 2007
A system of difference equations of the first order with meromorphic coefficients (not necessary periodic ones) subject to certain conditions of symmetry is analysed. These conditions arise in model problems of diffraction theory. A method for the constructive solution of the system of difference equations is proposed. It consists of three steps. First, it requires factorization of a certain function. Then, scalar integral equations with the same kernel and different right-hand sides should be solved. The kernel of the equations has a fixed singularity, and the solution belongs to a class of functions with a power singularity. Finally, arbitrary constants are fixed from some conditions which guarantee the equivalence of the original system of difference equations and the integral equations. The method is illustrated by solving a model electromagnetic problem of a plane wave diffracted from an anisotropic impedance half-plane at oblique incidence.
Keywords: system of difference equations; Riemann-Hilbert problem; integral equation; electromagnetic diffraction.