Semigroups Generated by Similarity Orbits of Semi-invertible Operators and Unitary Orbits of Isometries

It is proved that for a left invertible operator A, which is not a sum of a scalar and a compact operator, the semigroup generated by similarity orbit of A contains all left invertible operators with suitable (large enough) deficiency. A corresponding result holds for right invertible operators. For isometries, the same statement is proved for unitary orbits.     

Hypercyclic Semigroups Generated by Ornstein-Uhlenbeck Operators

The chaotic and hypercyclic behavior of the C ₀-semigroups of operators generated by a perturbation of the Ornstein-Uhlenbeck operator with a multiple of the identity in L²(\mathbb R^N){L^2(\mathbb {R}^N)} is investigated. Negative and positive results are presented, depending on the signs of the real parts of the eigenvalues of the matrix appearing in the drift of the operator.     

Feller Semigroups Generated by Degenerate Elliptic Operators

This paper is devoted to the functional analytic approach to the problem of construction of Feller semigroups with sticky boundary condition on various spaces of continuous functions, generalizing the previous work. More precisely we construct Feller semigroups corresponding to such a diffusion phenomenon that a Markovian particle moves continuously in the state space, sticking to the boundary.     

On Varieties Generated by Minimal Complex Semigroups

A semigroup is complex if it generates a variety the subvariety lattice of which contains an isomorphic copy of every finite lattice. It is known that a complex semigroup has at least four elements and that up to isomorphism and anti-isomorphism, there are four complex semigroups of order four. Subvarieties of the varieties generated by two of these four minimal complex semigroups have previously been described. To complete the study, we describe subvarieties of the varieties generated by the remaining two semigroups. This research was partially supported by the National Natural Science Foundation of China (No.10571077) and the Natural Science Foundation of Gansu Province (No.3ZS052-A25-017)     

Conservativeness of Semigroups Generated by Pseudo Differntial Operators

Assume that the pseudo differential operator -q(x,D) generates a Fellerian or sub-Markovian semigroup. Under some natural additional conditions on the symbol -q(x,) we prove that the operator -q(x,D) is conservative if and only if q(x,0)0.     

Finitely Generated Commutative Regular Semigroups

Abstract

In this paper we give a construction that allows us to describe up to isomorphisms all finitely generated regular commutative semigroups.     

Limiting Case for Interpolation Spaces Generated by Holomorphic Semigroups

tA )_t≥0 on X. We denote by X_A(θ,p), for 0 < θ < 1, the interpolation spaces of X and D(A) introduced by Berens and Butzer in [1]. These spaces play an important role in the approximation theory ( [2] ) as well as in the study of the abstract parabolic equation u′ (t) = Au(t) + f(t) ( [3] ). It has been proved in [6] that these spaces are meaningful (and still enjoy relevant properties) also in the case θ = 0. In this paper we continue the study of [6] and prove new interesting properties of these spaces.     

Commutative Noetherian Semigroups are Finitely Generated

Abstract. We provide a short proof that a commutative semigroup is finitely generated if its lattice of congruences is Noetherian.     

Embedding Semigroups into Idempotent Generated Ones

We present a concrete model of the embedding due to Pastijn and Yan of a semigroup S into an idempotent generated semigroup now in terms of a Rees matrix semigroup over S¹. The paper starts with a comparison of the two embeddings. Studying the properties of this embedding, we prove that it is functorial. We show that a number of usual semigroup properties is preserved by this embedding, such as periodicity, finiteness, the cryptic property, regularity, complete semisimplicity and various local properties, but complete regularity is not one of them.     

Embedding Semigroups into Idempotent Generated Ones

We present a concrete model of the embedding due to Pastijn and Yan of a semigroup S into an idempotent generated semigroup now in terms of a Rees matrix semigroup over S¹. The paper starts with a comparison of the two embeddings. Studying the properties of this embedding, we prove that it is functorial. We show that a number of usual semigroup properties is preserved by this embedding, such as periodicity, finiteness, the cryptic property, regularity, complete semisimplicity and various local properties, but complete regularity is not one of them.     

仿射酉群作用下的面轨道生成的格

设AUG(n,Fq2)是Fq2上的n维仿射酉空间,AUn(Fq2)是Fq2上的n次仿射酉群,设M(m,r)是AUn(Fq2)作用下的(m,r)面的轨道.用L(m,r)表示M(m,r)中面的交生成的集合.讨论了各轨道生成的集合之间的包含关系,一个面属于M(m,r)生成的集合的条件,以及L(m,r)是几何格的充要条件.     

Wold-Type Decompositions for Pairs of Commutative Semigroups Generated by Isometries

Functional Analysis and Its Applications - In this paper we analyze connections between Wold-type decompositions of bi/isometries and pairs of semigroups of isometries, where at least one of...     

仿射辛群作用下的面轨道生成的格

设ASU(2v,F_q)是F_q上的2v维仿射辛空间,ASp_(2v)(F_q)是F_q上的2v次仿射辛群,设M(m,s)是ASp_(2v)(F_q)作用下的(m,s)面的轨道,用L(m,s)表示M(m,s)中面的交生成的集合.讨论了各轨道生成的集合之间的包含关系,一个面是由给定M(m,s)生成的集合中的一个元素的条件,以及L(m,s)何时做成几何格.     

Exact Splitting Methods for Semigroups Generated by Inhomogeneous Quadratic Differential Operators

Foundations of Computational Mathematics - We introduce some general tools to design exact splitting methods to compute numerically semigroups generated by inhomogeneous quadratic differential...     

Growth Estimates for Semigroups Generated by 2Sx2 Operator Matrices

In this paper we give an explicit formula for semigroups generated by 2×2 operator matrices. Using this formula we can derive an estimate for the growth bound of the associated matrix generator. Finally these results are applied to a complete second order Cauchy problem yielding an explicit formula and a growth estimate for the solution of this problem.     

Embedding of Semigroups of Lipschitz Maps into Positive Linear Semigroups on Ordered Banach Spaces Generated by Measures

Interpretation, derivation and application of a variation of constants formula for measure-valued functions motivate our investigation of properties of particular Banach spaces of Lipschitz functions on a metric space and semigroups defined on their (pre)duals. Spaces of measures densely embed into these preduals. The metric space embeds continuously in these preduals, even isometrically in a specific case. Under mild conditions, a semigroup of Lipschitz transformations on the metric space then embeds into a strongly continuous semigroups of positive linear operators on these Banach spaces generated by measures.      

Exponential Stability of Semigroups Generated by Volterra Integro-Differential Equations with Singular Kernels

Differential Equations - In a separable Hilbert space, we study abstract linear inhomogeneous second-order Volterra integro-differential equations on the positive half-line with operator...