共查询到20条相似文献,搜索用时 823 毫秒
1.
Hafida Laasri 《Archiv der Mathematik》2018,111(2):187-201
Evolution families are the non-autonomous counterpart of operator semigroups in the well-posedness theory of non-autonomous evolution equations. This note is devoted to fundamental operator theoretical properties, beginning with norm continuity—which we regard as a fingerprint of analyticity. While no known analogue of analytic semigroups is known in the non-autonomous case, we give a sufficient condition for norm-continuity of evolution families. Furthermore, we develop a theory of compact and trace class evolution families. The abstract results are applied to the Laplace operator with time dependent Robin boundary conditions. 相似文献
2.
Perturbations leading to an estimate of the rate of convergence to an asynchronous equilibrium of general semigroups with boundary conditions are given. The particular case of translation semigroups is examined. The results obtained are applied to a demographic model. 相似文献
3.
主要运用Laplace-Stieltjes的方法,讨论Hilbert空间上α-次预解算子族的依范连续性与其预解式的关系,得到一个主要结果:Hilbert空间上α-次预解算子族的依范连续性与其预解式在当|τ|→∞时,‖(ω+iτ)~(α-1)R((ω+iτ)~α,A)‖→0等价. 相似文献
4.
Larbi Alaoui 《Semigroup Forum》2001,63(3):330-356
In this paper nonlinear homogeneous retarded differential equations and models from population dynamics and epidemiology
are considered and studied by the use of translation semigroup theory. We show that the corresponding solution semigroups
are equivalent to appropriate translation semigroups. Existence results for the retarded equations are established by taking
the space of initial functions of the form W
1,p
((-r,0),F) where F is a Banach space, 1≤ p<∈fty and 0<r\le∈fty .
June 28, 1999 相似文献
5.
In this paper we present a new approach to construct the set of numerical semigroups with a fixed genus. Our methodology is based on the construction of the set of numerical semigroups with fixed Frobenius number and genus. An equivalence relation is given over this set and a tree structure is defined for each equivalence class. We also provide a more efficient algorithm based on the translation of a numerical semigroup to its so-called Kunz-coordinates vector. 相似文献
6.
Semigroup Forum - In this paper, we study the $${\mathcal {F}}$$ -transitive behaviour of the translation semigroups on complex sectors, where $${\mathcal {F}}$$ is a Furstenberg family of the... 相似文献
7.
In this paper we introduce the concept of modular translation. With this tool, if we consider a certain numerical semigroup S, we build another one S′ whose principal invariants are given explicitly in terms of the invariants of S. Some results about irreducible numerical semigroups are also studied. 相似文献
8.
9.
In this survey paper we present some recent results in the iteration theory. Mainly, we focus on the problems concerning real iteration groups (flows) and semigroups (semiflows) such as existence, regularity and embeddability. We also discuss some issues associated to the problem of embedddability, i.e. iterative roots and approximate iterability. The topics of this paper are: (1) measurable iteration semigroups; (2) embedding of diffeomorphisms in regular iteration semigroups in \({{\mathbb{R}}^n}\) space; (3) iteration groups of fixed point free homeomorphisms on the plane; (4) embedding of interval homeomorphisms with two fixed points in a regular iteration group; (5) commuting functions and embeddability; (6) iterative roots; (7) the structure of iteration groups on an interval; (8) iteration groups of homeomorphisms of the circle; (9) approximately iterable functions; (10) set-valued iteration semigroups; (11) iterations of mean-type mappings; (12) Hayers–Ulam stability of the translation equation. Most of the results presented here was obtained by the means of functional equations. We indicate the relations between the iteration theory and functional equations. 相似文献
10.
众所周知,Clifford半群是正则半群类中的一类重要半群,本文定义正规 Ehresmann型wrpp半群,它是Clifford半群在wrpp半群类中的推广,给出了此类半群的若干刻划. 相似文献
11.
A remark on the Frequent Hypercyclicity Criterion for weighted composition semigroups and an application to the linear von Foerster–Lasota equation 下载免费PDF全文
T. Kalmes 《Mathematische Nachrichten》2016,289(8-9):982-993
We generalize a result for the translation C0‐semigroup on about the equivalence of being chaotic and satisfying the Frequent Hypercyclicity Criterion due to Mangino and Peris 8 to certain weighted composition C0‐semigroups. Such C0‐semigroups appear in a natural way when dealing with initial value problems for linear first order partial differential operators. We apply our result to the linear von Foerster–Lasota equation arising in mathematical biology. Weighted composition C0‐semigroups on Sobolev spaces are also considered. 相似文献
12.
In this paper, we introduce an important subclass of quasiregular semigroups, namely the class of C*-quasiregular semigroups. This class of semigroups contains the classes of Clifford semigroups, quasi Clifford semigroups, C-quasiregular semigroups and their generalizations as its subclasses. Some characterization theorems for such semigroups are obtained. The structure of this kind of quasiregular semigroups is investigated by using the generalized ?-product of some semigroups on a semilattice Y. Construction techniques of such classes of semigroups are particularly demonstrated. 相似文献
13.
We study a class of special strongly rpp semigroups, namely, the class of super rpp semigroups. These super rpp semigroups
are generalizations of both superabundant semigroups and Clifford semigroups within the class of rpp semigroups. In particular,
we prove that a super rpp semigroup is a semilattice of D
(l)-simple strongly rpp semigroups. Our result not only generalizes a well-known theorem of Clifford in the class of completely
regular semigroups but also strengthens some structure theorems obtained by Ren-Shum for superabundant semigroups which are
orthodox. Some special super rpp semigroups are considered and discussed. 相似文献
14.
15.
Yu. N. Orlov V. Zh. Sakbaev 《Proceedings of the Steklov Institute of Mathematics》2018,301(1):197-206
The notion of Chernoff equivalence for operator-valued functions is generalized to the solutions of quantum evolution equations with respect to the density matrix. A semigroup is constructed that is Chernoff equivalent to the operator function arising as the mean value of random semigroups. As applied to the problems of quantum optics, an operator is constructed that is Chernoff equivalent to a translation operator generating coherent states. 相似文献
16.
V. A. Molchanov 《Semigroup Forum》1983,27(1):155-199
At present, there are quite a few investigations in the theory of semigroups devoted to semigroups of mappings on graphs. Up to now, endomorphism semigroups of graphs, extensive transformation semigroups of graphs, coloring semigroups of graphs and other semigroups of special mappings on graphs have been studied. The results obtained show the way graphs are determined by the above-mentioned semigroups. They also show the structure of semigroups of mappings and interrelations between properties of graphs and corresponding properties of semigroups associated with the graphs. This paper gives a survey of the main results in this field. 相似文献
17.
本文介绍纯整Ehresmann半群.纯整Ehresmann半群是一类特殊的U-半富足半群,我们给出了这类半群的若干刻划,并讨论了一些特殊的纯整Ehresmann半群. 相似文献
18.
We consider a class of Feller semigroups on Lie groups which fail to commute with left translation due to the existence of a cocycle h which is identically one for Lévy processes. Under certain conditions, we are able to show that the infinitesimal generator of such a semigroup has the Lévy–Khintchine–Hunt form but with variable characteristics, thus we obtain an extension of classical work in Euclidean space by Courrège. 相似文献
19.
Valdis Laan 《Periodica Mathematica Hungarica》2010,60(1):81-94
Two semigroups are called strongly Morita equivalent if they are contained in a Morita context with unitary bi-acts and surjective
mappings. We consider the notion of context equivalence which is obtained from the notion of strong Morita equivalence by
dropping the requirement of unitariness. We show that context equivalence is an equivalence relation on the class of factorisable
semigroups and describe factorisable semigroups that are context equivalent to monoids or groups, and semigroups with weak
local units that are context equivalent to inverse semigroups, orthodox semigroups or semilattices. 相似文献
20.
《Nonlinear Analysis: Real World Applications》2008,9(5):1905-1917
This paper deals with a nonlinear semigroup approach to semilinear initial-boundary value problems which model nonlinear age structured proliferating cell population dynamics. The model involves age-dependence and cell cycle length, and boundary conditions may contain compositions of nonlinear functions and trace of solutions. Hence the associated operators are not necessarily formulated in the form of continuous perturbations of linear operators. A family of equivalent norms is introduced to discuss local quasidissipativity of the operators and a generation theory for nonlinear semigroups is employed to construct solution operators. The resultant solution operators are obtained as nonlinear semigroups which are not quasicontractive but locally equi-Lipschitz continuous. 相似文献