We consider the Fröbenius–Perron semigroup of linear operators associated to a semidynamical system defined in a topological space X endowed with a finite or a σ–finite regular measure. Assuming strong continuity for the Fröbenius–Perron semigroup of linear operators in the space Lμ(X) or in the space Lμ(X) for 1 < p <∞ ([11]). We study in this article ergodic properties of the Fröbenius–Perron...

Recently, there has been significant development in the existence of mild solutions for fractional semilinear integro-differential equations but optimal control is not provided. The aim of this paper is studying optimal feedback control for fractional semilinear integro-differential equations in an arbitrary Banach space associated with operators ...

We prove that the ring of differential operators of any semigroup algebra is finitely generated. In contrast, we also show that the graded ring of the order filtration on the ring of differential operators of a semigroup algebra is finitely generated if and only if the semigroup is scored.  2004 Elsevier Inc. All rights reserved.

We prove a new representation of the generator of a subordinate semigroup as limit of bounded operators. Our construction yields, in particular, a characterization of the domain of the generator. The generator of a subordinate semigroup can be viewed as a function of the generator of the original semigroup. For a large class these functions we show that operations at the level of functions has ...

This paper is concerned with emptyness of the essential spectrum, or equivalently compactness of the semigroup, for perturbations of selfadjoint operators that are bounded below (on an L2-space). For perturbations by a (nonnegative) potential we obtain a simple criterion for compactness of the semigroup in terms of relative compactness of the operators of multiplication with characteristic func...

This paper studies algebras of operators associated to a semigroup algebra. The ring of differential operators is shown to be anti-isomorphic to the symmetry algebra and both are described explicitly in terms of the semigroup. As an application, we produce a criterion to determine the equivalence of A-hypergeometric systems. Conditions under which associated algebras are finitely generated are ...

this paper proves the existence and uniqueness of quadratic mean almost periodic mild so-lutions for a class of stochastic dierential equations in a real separable hilbert space. themain technique is based upon an appropriate composition theorem combined with the banachcontraction mapping principle and an analytic semigroup of linear operators.