On Unitary Equivalence of Analytic Toeplitz Operators

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Semigroups of Transformations Preserving an Equivalence Relation and a Cross-Section

Abstract

For a set X, an equivalence relation ρ on X, and a cross-section R of the partition X/ρ induced by ρ, consider the semigroup T(X, ρ, R) consisting of all mappings a from X to X such that a preserves both ρ (if (x, y)?∈?ρ then (xa, ya)?∈?ρ) and R (if r?∈?R then ra?∈?R). The semigroup T(X, ρ, R) is the centralizer of the idempotent transformation with kernel ρ and image R. We determine the structure of T(X, ρ, R) in terms of Green's relations, describe the regular elements of T(X, ρ, R), and determine the following classes of the semigroups T(X, ρ, R): regular, abundant, inverse, and completely regular.     

带幂非线性项变系数非线性波动方程的李对称分类与等价性变换

从微分方程群理论分析角度,研究了一类含有3个任意函数和2个幂非线性项的变系数非线性波动方程.由于方程具有很强的任意性和非线性项,可通过等价性变换寻找方程的不变对称分类.首先给出了等价性变换的一般结果,其中包括一些包含任意元的非局部变换.然后对所研究的方程,利用广义扩展等价群和条件等价群给出了方程的完全对称分类.最后获得并分析了方程的特殊类相似解.     

On Equivalence Relations in Ordered Sets

A relationship between equivalence relations in finite ordered sets and linear decompositions is presented.     

Symmetric Operations on Equivalence Relations

A new binary operation on the family of equivalence relations was introduced and studied by Britz, Mainetti, and Pezzoli. In this paper we give an equivalent, easier to grasp, definition of the same binary operation, and we prove it to be just an example of a bigger family of binary operations, which are shown to have interesting interpretation and meaning.AMS Subject Classification: 05A18, 05C90, 03E02, 91D30.     

Recursively Enumerable Equivalence Relations Modulo Finite Differences

We investigate the upper semilattice Eq* of recursively enumerable equivalence relations modulo finite differences. Several natural subclasses are shown to be first-order definable in Eq*. Building on this we define a copy of the structure of recursively enumerable many-one degrees in Eq*, thereby showing that Th(Eq*) has the same computational complexity as the true first-order arithmetic. Mathematics Subject Classification: 03D25, 03D15, 03D35.     

模糊子坡代数、模糊等价关系及模糊同余关系的序方面

证明了坡代数(X,+,*)上所有模糊子坡代数构成的集合(SI[0.1](X,+,*),≤),所有模糊理想构成的集合(Id[0.1](X,+,*),≤),所有模糊滤子构成的集合(Fil[0.1](X,+,*),≤)都是([0,1]x,≤)的子完备格,所有模糊等价关系构成的集合(Equ[0.1](X,+,*),≤),所有模...     

Analytic Extension of Functions from Analytic Hilbert Spaces

Let M be an invariant subspace of Hv2. It is shown that for each f∈M⊥, f can be analytically extended across (?)Bd\σ(Sz1,…, Szd).     

Analytic completeness theorem for singular biprobability models

The aim of the paper is to prove tha analytic completeness theorem for a logic L(∫₁, ∫₂)_A^s with two integral operators in the singular case. The case of absolute continuity was proved in [4]. MSC: 03B48, 03C70.     

Equivalence of some quadratic programming algorithms

We formulate a general algorithm for the solution of a convex (but not strictly convex) quadratic programming problem. Conditions are given under which the iterates of the algorithm are uniquely determined. The quadratic programming algorithms of Fletcher, Gill and Murray, Best and Ritter, and van de Panne and Whinston/Dantzig are shown to be special cases and consequently are equivalent in the sense that they construct identical sequences of points. The various methods are shown to differ only in the manner in which they solve the linear equations expressing the Kuhn-Tucker system for the associated equality constrained subproblems. Equivalence results have been established by Goldfarb and Djang for the positive definite Hessian case. Our analysis extends these results to the positive semi-definite case. This research was supported by the Natural Sciences and Engineering Research Council of Canada under Grant No. A8189.     

Categories of Relations and Functional Relations

We define relations and their composition in a category with (E, M)-factorization structure, with M consisting of monomorphisms, but E not restricted to epimorphisms. We obtain an associativity criterion for composition of relations, and we study functional and induced relations. We show that under our assumptions, the categories of relations on functional and induced relations are isomorphic to the category of relations for the given category.     

包络半群与拓扑动力学中的接近关系

运用包络半群的理论，对接近关系中一个重要定理给出了一个简单证明．作为这一定理的应用，我们得到接近关系可乘性的一个结果．并且对另一种接近关系，也得到一个结果．这两个定理减弱了Ｃｌａｙ在这一领域中两个定理的条件．     

Analytic norms in Orlicz spaces

It is shown that an Orlicz sequence space admits an equivalent analytic renorming if and only if it is either isomorphic to or isomorphically polyhedral. As a consequence, we show that there exists a separable Banach space admitting an equivalent -Fréchet norm, but no equivalent analytic norm.

     

单位圆内解析系数的高阶齐次线性微分方程解与小函数的关系

本文对系数为单位圆内的解析函数的某类高阶齐次线性微分方程解的性质进行研究,得到解的增长级和超级的精确估计以及解与小函数之间的关系.     

等价关系的判定及性质

设R是集合A上的二元关系,要判定R在A上是否是等价关系,一般来讲,只能从定义出发,当R包含的序偶较多时,从定义出发又比较难于判定.从关系矩阵出发,给出一种判定方法,并讨论等价关系的矩阵性质.     

Analytic solutions of Volterra equations via semigroups

We show that solutions of Volterra integrodifferential equations are analytic provided the leading operator generates an analytic semigroup and the convolution kernel is in a space of analytic functions. Similar results have been obtained via Laplace transform, so far. We show that it is possible to obtain such results using a semigroup approach.