We study a boundary value problem for a system of the third order semi-linear partial differential equations with nonlocal boundary conditions. We establish sufficient conditions of existence, uniqueness, regularity and sign-preserving property of solutions of the studied problem and construct an iterative method for its approximation.@en

We construct the modification of the two-sided method with improved characteristics of convergence for approximate integration of boundary-value problem for systems of secondorder non-linear differential equations of the hyperbolic type on the plane when the bound of the domain of the independent variables consists of the pair of characteristics.@en