# Kapustyan O. V.

### Stability of global attractors of impulsive infinite-dimensional systems

Kapustyan O. V., Perestyuk N. A., Romanyuk I. V.

Ukr. Mat. Zh. - 2018. - 70, № 1. - pp. 29-39

The stability of global attractor is proved for an impulsive infinite-dimensional dynamical system. The obtained abstract results are applied to a weakly nonlinear parabolic equation whose solutions are subjected to impulsive perturbations at the times of intersection with a certain surface of the phase space.

### Global attractors of impulsive infinite-dimensional systems

Kapustyan O. V., Perestyuk N. A.

Ukr. Mat. Zh. - 2016. - 68, № 4. - pp. 517-528

We study the existence of global attractors in discontinuous infinite-dimensional dynamical systems, which may have trajectories with infinitely many impulsive perturbations. We also select a class of impulsive systems for which the existence of a global attractor is proved for weakly nonlinear parabolic equations.

### Approximate Synthesis of Distributed Bounded Control for a Parabolic Problem with Rapidly Oscillating Coefficients

Ukr. Mat. Zh. - 2015. - 67, № 3. - pp. 355-365

We study the problem of finding the optimal control in the form of feedback (synthesis) for a linear-quadratic problem in the form of a parabolic equation with rapidly oscillating coefficients and distributed control on the right-hand side (whose Fourier coefficients obey certain restrictions in the form of inequalities) and a quadratic quality criterion. We deduce the exact formula of synthesis and justify its approximate form corresponding to the replacement of rapidly oscillating coefficients by their averaged values.

### Approximate stabilization for a nonlinear parabolic boundary-value problem

Kapustyan O. A., Kapustyan O. V., Sukretna A. V.

Ukr. Mat. Zh. - 2011. - 63, № 5. - pp. 654-661

For a problem of optimal stabilization of solutions of a nonlinear parabolic boundary-value problem with small parameter of a nonlinear summand, we justify the form of approximate regulator on the basis of the formula of optimal synthesis of the corresponding linear quadratic problem.

### On positive solutions of one class of evolutionary inclusions of the subdifferential type

Kapustyan O. V., Shklyar T. B.

Ukr. Mat. Zh. - 2011. - 63, № 4. - pp. 472-480

Sufficient conditions of the existence of a nonnegative solution are obtained for an evolution inclusion of subdifferential type with multivalued non-Lipschitz perturbation. Under the additional condition of dissipativity, the existence of the global attractor in the class of nonnegative functions is proved.

### On the existence of global attractors for one class of cascade systems

Ukr. Mat. Zh. - 2004. - 56, № 9. - pp. 1287-1291

We investigate the qualitative behavior of solutions of cascade systems without uniqueness. We prove that solutions of a reaction-diffusion system perturbed by a system of ordinary differential equations and solutions of a system of equations of a viscous incompressible liquid with passive components form families of many-valued semiprocesses for which a compact global attractor exists in the phase space.

### Random attractors for ambiguously solvable systems dissipative with respect to probability

Ukr. Mat. Zh. - 2004. - 56, № 7. - pp. 892–900

We prove a theorem on the existence of a random attractor for a multivalued random dynamical system dissipative with respect to probability. Abstract results are used for the analysis of the qualitative behavior of solutions of a system of ordinary differential equations with continuous right-hand side perturbed by a stationary random process. In terms of the Lyapunov function, for an unperturbed system, we give sufficient conditions for the existence of a random attractor.

### Global Attractor for a Nonautonomous Inclusion with Discontinuous Right-Hand Side

Kapustyan O. V., Kasyanov P. O.

Ukr. Mat. Zh. - 2003. - 55, № 11. - pp. 1467-1475

We consider a nonautonomous inclusion the upper and lower selectors of whose right-hand side are determined by functions with discontinuities of the first kind. We prove that this problem generates a family of multivalued semiprocesses for which there exists a global attractor compact in the phase space.

### Global Attractor of an Evolution Inclusion with Pulse Influence at Fixed Moments of Time

Kapustyan O. V., Perestyuk N. A.

Ukr. Mat. Zh. - 2003. - 55, № 8. - pp. 1058-1068

We consider an autonomous evolution inclusion with pulse perturbations at fixed moments of time. Under the conditions of global solvability, we prove the existence of a minimal compact set in the phase space that attracts all trajectories.

### Averaged Synthesis of the Optimal Control for a Wave Equation

Kapustyan O. V., Sukretna A. V.

Ukr. Mat. Zh. - 2003. - 55, № 5. - pp. 612-620

For a wave equation, we determine an optimal control in the feedback form and prove the convergence of the constructed approximate control to the exact one.

### Global Attractor of One Nonlinear Parabolic Equation

Kapustyan O. V., Shkundin D. V.

Ukr. Mat. Zh. - 2003. - 55, № 4. - pp. 446-455

We apply the theory of multivalued semiflows to a nonlinear parabolic equation of the “reaction–diffusion” type in the case where it is impossible to prove the uniqueness of its solution. A multivalued semiflow is generated by solutions satisfying a certain estimate global in time. We establish the existence of a global compact attractor in the phase space for the multivalued semiflow generated by a nonlinear parabolic equation. We prove that this attractor is an upper-semicontinuous function of a parameter.

### Attractors of Differential Inclusions and Their Approximation

Ukr. Mat. Zh. - 2000. - 52, № 7. - pp. 975-979

We investigate the properties of solutions of differential inclusions in a Banach space. We prove a theorem on the existence of a global attractor for a multivalued semidynamical system generated by these solutions and a theorem on the approximation of an attractor in the Hausdorff metric.

### An attractor of a semiflow generated by a system of phase-field equations without the uniqueness of a solution

Ukr. Mat. Zh. - 1999. - 51, № 7. - pp. 1006–1009

We prove the existence of a global compact attractor for a multivalued semiflow generated by a system of phase-field equations with conditions on nonlinearity that do not guarantee the uniqueness of a solution.