We consider solution semigroups associated with a linear scalar neutral equation on weighted product spaces. We select the weight function to guarantee optimal, or close to optimal, growth rate estimates on the semigroup. Then we show that the so-calledàveraging' approximation scheme preserves these growth rate estimates of the original system, uniformly in the discretization parameter.

We formulate the dynamics of an infinitely extended open dissipative quantum system , Σ, in Schroedinger picture. The generic model on which this is based comprises a C★-algebra, A observables, folium, ℱ states algebra and one-parameter semigroup, τ linear transformations that represents its given by natural infinite-volume limit corresponding semigroup for finite system. On basis, we establish...

The aim of this paper is to classify all monogenic ternary semigroups, up to isomorphism. We divide them to two groups: finite and infinite. We show that every infinite monogenic ternary semigroup is isomorphic to the ternary semigroup O, the odd positive integers with ordinary addition. Then we prove that all finite monogenic ternary semigroups with the same index...

If T t = e Zt is a positive one-parameter contraction semigroup acting on l p (X) where X is a countable set and 1 ≤ p < ∞, then the peripheral point spectrum P of Z cannot contain any non-zero elements. The same holds for Feller semigroups acting on L p (X) if X is locally compact.

1 We study relationships between Logarithmic Sobolev inequalities with one parameter of Davies-Simon type, energy-entropy inequality, Nash-type inequality and Sobolev-type inequalities. The inequalities of Sobolev-type apply in the general setting of symmetric sub-Markovian semigroups (and some generalizations). We provide several examples of application of theses results for ultracontractive s...

If Tt = eZt is a positive one-parameter contraction semigroup acting on lp(X) where X is a countable set and 1 ≤ p < ∞, then the peripheral point spectrum P of Z cannot contain any non-zero elements. The same holds for Feller semigroups acting on Lp(X) if X is locally compact.

This paper studies FA-presentable structures and gives a complete classification of the finitely generated FA-presentable cancellative semigroups. We show that a finitely generated cancellative semigroup is FA-presentable if and only if it is a subsemigroup of a virtually abelian group.

–a notion of amenability for topological semigroups is introduced. a topological semigroup s iscalled johnson amenable if for every banach s -bimodule e , every bounded crossed homomorphism froms to e* is principal. in this paper it is shown that a discrete semigroup s is johnson amenable if and only if1(s) is an amenable banach algebra. also, we show that if a topological semigroup s is johns...

In this paper, we give some characterizations of intraregular semigroups by the properties of their (∈,∈ ∨qk)-fuzzy right ideals, (∈,∈ ∨qk)-fuzzy left ideals, (∈,∈ ∨qk)-fuzzy interior ideals, (∈,∈ ∨qk)fuzzy bi-ideals and (∈,∈ ∨qk)-fuzzy generalized bi-ideals. 2010 AMS Classification: 03E72, 20M12

We investigate the class of quasitrivial semigroups and provide various characterizations of the subclass of quasitrivial and commutative semigroups as well as the subclass of quasitrivial and order-preserving semigroups. We also determine explicitly the sizes of these classes when the semigroups are defined on finite sets. As a byproduct of these enumerations, we obtain several new integer seq...