Relaxation and existence of optimal controls for systems governed by evolution inclusions in separable Banach spaces

In this paper, we examine relaxed control systems governed by evolution inclusions in a separable Banach space. First, we establish the existence of admissible trajectories, correcting an earlier result of Ahmed. Then, we obtain a compactness result for the set of admissible trajectories. Using this compactness result, we prove the existence of optimal solutions for optimal control problems; furthermore, we show that the values of the original and relaxed problems are equal. Finally, we show that the original trajectories are dense in the set of relaxed trajectories. An example is worked out.This research was supported by NSF Grant No. DMS-86-02313.     

Multiplicity of solutions for the bounce problem

The bounce trajectories in a convex set which assume assigned positions in two fixed time instants are sought. Sufficient conditions in order to obtain the existence of infinitely many bounce trajectories are found.     

Dynamical systems with multivalued integrals on a torus

Properties of the solutions to differential equations on the torus with a complete set of multivalued first integrals are considered, including the existence of an invariant measure, the averaging principle, and the infiniteness of the number of zeros for integrals of zero-mean functions along trajectories. The behavior of systems with closed trajectories of large period is studied. It is shown that a generic system acquires a limit mixing property as the periods tend to infinity.     

On open-loop and feedback attainability of a closed set for nonlinear control systems

In this note, we investigate the existence of controls which allow to reach a given closed set K through trajectories of a nonlinear control system. In the case where the set is sufficiently regular we give a condition allowing to find a feedback control law which ensures the existence of trajectories to reach the set. We also consider the case where all the trajectories reach K. When K is not necessarily attainable but only viable, we build a set-valued feedback for which the set is invariant. Our approach concerns continuous dynamics, possibly not C¹, so our methods do not come from geometric control theory. Furthermore, we do not require any regularity of the set K in order to obtain our results, except when we want to establish the existence of a feedback control law to achieve our goals.     

On the Existence of a Lipschitz Feedback Control in a Control Problem with State Constraints

We consider a nonlinear control system with state constraints given as a solution set for a finite system of nonlinear inequalities. The problem of constructing a feedback control that ensures the viability of trajectories of the closed system in a small neighborhood of the boundary of the state constraints is studied. Under some assumptions, the existence of a feedback control in the form of a Lipschitz function of the state of the system is proved.     

Existence of a value in semidynamical games

The games (generalizing differential games) in which the dynamics of players is described by k-semidynamical systems are called semidynamical games. For such games two theorems on the existence of a value in the class of piecewise program strategies are proved. Examples are given to show that the conditions of these theorems impose very weak restrictions on the set of admissible controls of the players and, in the games with a fixed duration, on the set of trajectories of semidynamical systems. Translated from Matematicheskie Zametki, Vol. 22, No. 3, pp. 401–410, September, 1977.     

Solution of one of Birkhoff''s problems : PMM vol. 42, no. 6, 1978, pp. 1136–1141

The criterion of existence of an integral linear with respect to generalized velocities over the set of trajectories with the same total energy is proved for conservative dynamic systems with two degrees of freedom.     

The isolated invariant sets of a flow

Some definitions such as m-chain recurrent set, weakly gradient flow and generalized Morse decomposition for a flow defined on a topological space are introduced in this paper. Some conclusions, include the chain recurrent set contain the m-chain recurrent set; the m-chain recurrent set contain the non-wandering set, are proved. In some flows the non-wandering set is proper subset of the m-chain recurrent set; in the meantime the m-chain recurrent set is proper subset of the chain recurrent set. Moreover some criterions for the existence of trajectories joining singular points and a necessary and sufficient condition of the weakly gradient flow are also given here. At last the generalized Morse decomposition of the invariant set are discussed in the paper.     

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

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.     

Approximate construction of the set of trajectories of the control system described by a Volterra integral equation

In this paper the set of trajectories of the control system is investigated. It is assumed that the behavior of the control system is described by a Volterra integral equation which is nonlinear with respect to the state vector and is affine with respect to the control vector, and the control functions have an integral constraint. An approximation of the set of trajectories by the set which consists of a finite number of trajectories is given. The Hausdorff distance between the set of trajectories of the system and the set, consisting of a finite number of trajectories is evaluated.     

Continuous selection of the solution map for one-sided Lipschitz differential inclusions

In the paper we deal with differential inclusions with one-sided Lipschitz (OSL) continuous right-hand sides, and prove the existence of a continuous selection of the solution map which assigns to any point the set of solutions to the multivalued Cauchy problem. As an application we study the problem of the existence of viable trajectories in a prescribed closed subset of a Banach space via the generalized Wa?ewski retract method.     

Rest points of generalized dynamical systems

In this paper we consider generalized dynamical systems whose integral vortex (that is, the set of all trajectories of the system starting at a given point) is an acyclic set in the corresponding space of curves. For such systems we apply the theory of fixed points for multi-valued maps in order to prove the existence of rest points. In this way we obtain new existence theorems for rest points of generalized dynamical systems. Translated fromMatematicheskie Zametki, Vol. 65, No. 1, pp. 28–36, January, 1999.     

一类具两条不连续相交线的平面系统的闭轨

研究了一类具两条不连续相交线的平面系统的闭轨.利用微分包含理论和点变换的方法,获得了一些有趣的结果,包括滑模解,同宿解和闭轨的存在性.同时给出了闭轨存在的必要条件.     

An existence theorem and some properties of maximum a posteriori estimators of trajectories of diffusions

A Maximum A Posteriori (MAP) estimator for trajectories of diffusions observed via a noisy non-linear sensor, defined in [1] for diffusions evolving in "flat" spaces, is extended to arbitrary nondegenerate diffusions in W (subject to some technical constraints). An existence theorem for the MAP trajectories estimator is proved. Finally, relations between the trajectories MAP estimator and the pointwise MAP estimator are demonstrated. Some open problems concerning the issue of finite dimensionality of the MAP trajectories estimator are pointed out     

The qualitative analysis of a class of planar Filippov systems

We use the theory of differential inclusions, Filippov transformations and some appropriate Poincaré maps to discuss the special case of two-dimensional discontinuous piecewise linear differential systems with two zones. This analysis applies to uniqueness and non-uniqueness for the initial value problem, stability of stationary points, sliding motion solutions, number of closed trajectories, existence of heteroclinic trajectories connecting two saddle points forming a heteroclinic cycle and existence of the homoclinic trajectory     

半线性抛物型方程定义的光滑强单调流收敛于半渐近稳定的奇点

本文研究半线性抛物型方程定义的光滑强单调流的渐近性态，我们给出了具有有界轨线且不收敛于半渐近稳定奇点的点集在Ｘ￣α中是第一范畴的充要条件，我们还研究了全有序奇点弧的存在性和非平凡不变函数的存在性之间的等价关系。     

The existence and uniqueness of trajectories joining critical points for differential equations in R3

In this paper, we prove the existence and uniqueness of trajectories joining critical points for differential equations in R³ by constructing the index pair of the isolated invariant set and using Conley index theory.     

Optimal control of nonlinear evolution inclusions

In this paper, we study the optimal control of nonlinear evolution inclusions. First, we prove the existence of admissible trajectories and then we show that the set that they form is relatively sequentially compact and in certain cases sequentially compact in an appropriate function space. Then, with the help of a convexity hypothesis and using Cesari's approach, we solve a general Lagrange optimal control problem. After that, we drop the convexity hypothesis and pass to the relaxed system, for which we prove the existence of optimal controls, we show that it has a value equal to that of the original one, and also we prove that the original trajectories are dense in an appropriate topology to the relaxed ones. Finally, we present an example of a nonlinear parabolic optimal control that illustrates the applicability of our results.This research was supported by NSF Grant No. DMS-88-02688.     

Nonconvex variational problem with recursive integral functionals in Sobolev spaces: Existence and representation

The purpose of this paper is twofold. First, we present the existence theorem of an optimal trajectory in a nonconvex variational problem with recursive integral functionals by employing the norm-topology of a weighted Sobolev space. We show the continuity of the integral functional and the compactness of the set of admissible trajectories. Second, we show that a recursive integrand is represented by a normal integrand under the conditions guaranteeing the existence of optimal trajectories. We also demonstrate that if the recursive integrand satisfies the convexity conditions, then the normal integrand is a convex function. These results are achieved by the application of the representation theorem in Lp-spaces.     

Time-optimal solution of a linear evolution equation in Banach spaces

The problem is that of finding trajectories of a linear evolution equation connecting two prescribed sets of states, initial and terminal, in the shortest possible time. Necessary conditions for the existence of solutions, i.e., time-optimum trajectories, are given in the form of a maximum principle.