On behavior of solutions of nonlinear differential equations in Hilbert space. II.
A general theorem (principle of a priori boundedness) on solvability of the boundary value problem is established, where is a vector-function belonging to the Carathéodory class corresponding to the matrix-function with bounded total variation components, and is a continuous operator. Basing on the mentioned principle of a priori boundedness, effective criteria are obtained for the solvability of the system under the condition where
This paper presents sufficient conditions for the existence of solutions to boundary-value problems of second order multi-valued differential inclusions. The existence of extremal solutions is also obtained under certain monotonicity conditions.
This paper is concerned with the asymptotic behavior of solutions of nonlinear differential equations of the third-order with quasiderivatives. We give the necessary and sufficient conditions guaranteeing the existence of bounded nonoscillatory solutions. Sufficient conditions are proved via a topological approach based on the Banach fixed point theorem.