Andrey V. Asymptotic properties of solutions of systems functional differential equations of neutral type.

Existence of periodic solutions of the systems of linear and nonlinear functional differential equations of neutral type with extremity quantity, nonlinear deviations of argument is investigated, the method of their construction has been developed and their properties are studied in the thesis has been developed. Conditions of the existence of continuously differentiable bounded for solutions of one boundary value problem for a systems of linear and nonlinear difference differential equations of neutral type have been obtained, the method of their construction has been developed and investigate the asymptotic properties of these solutions. For systems of nonlinear functional differential equations with nonlinear deviations of argument that depend on an unknown function, the study сonditions of the existence of continuously differentiable bounded for solutions and investigate the properties of these solutions. The structure of the set of solutions, continuously differentiable, of one limit problem for systems of nonlinear functional differential equations of neutral type with nonlinear deviations of argument that depend on an unknown function has been developed.