“…The proved Theorem 3 generalizes analogous statements for various boundary value problem for the differential equations [5,14,17]. The proved Theorem 3 also generalizes analogous statements for periodic boundary value problem for a matrix Riccati equation [4]. The length " of the segment OE0; " on which the iterative procedure (2.14) converges to the required solution of the boundary value problem (1.1), (1.2) can be estimated by analogy with [7,8,14].…”