Givi Khuskivadze, Vakhtang Kokilashvili, and Vakhtang Paatashvili

Boundary Value Problems for Analytic and Harmonic Functions in Domains with Nonsmooth Boundaries.

abstract:
In the present monograph, on the basis of the Cauchy type integral theory discontinuous boundary value problems for analytic functions with oscillating conjugacy coefficients and boundaries are studied. For analytic functions from Smirnov classes, the complete solution of the Riemann-Hilbert problem in domains with arbitrary piecewise smooth boundaries is presented. On the basis of the investigation of the linear conjugation problem, the boundary properties of derivatives of functions conformally mapping the unit circle onto a domain admitting a boundary with tangential oscillation less than $\pi$, are studied. From new representations derived for the above-mentioned functions, some well-known results of Lindel\"{o}f, Kellog and Warschawski as well as their generalizations are obtained; the Dirichlet and Neumann problems for harmonic functions from Smirnov classes are investigated; the picture of solvability is described completely; the non-Fredholm case is exposed; an influence of geometric properties of boundaries on the solvability is revealed; in all cases of solvability explicit formulas for the solutions in terms of Cauchy type integrals and conformally mapping functions are given.

Mathematics Subject Classification: 30E20, 30E25, 35Q15, 45E05, 42B20, 46E40, 30C35, 26A39, 35C05, 35J25.

Key words and phrases: Analytic and harmonic functions, discontinuous boundary value problem of linear conjugation, oscillating conjugacy coefficients, Riemann-Hilbert problem, factorization of functions, piecewise smooth boundary, angular points, cusps, Carleson curves, Cauchy type integrals, singular integrals, the Muckenhoupt $A_p$ condition, two-weight inequality, $A$- and $B$-integrals, $\wt{L}$-integral, Cauchy type $\wt{L}$ -integral, conformal mapping, Hardy and Smirnov classes, Dirichlet and Neumann problems.