幂群与序关系

设Ｇ为非ｍｏｎｏｉｄａｌ群，Ｅ是它的正规子集，满足Ｅ²＝Ｅ并且１_Ｇ∈／Ｅ．利用Ｅ作为正锥，可以在Ｇ上定义一个偏序，并且Ｇ成为一个偏序群．这样就可以利用这个序关系同时研究群Ｇ以及Ｇ上的以Ｅ为单位元的幂群．当Ｅ是极大子半群时，得到Ｇ的一个结构定理；在Ｇ是格序群的条件下，Ｇ上的幂群Γ可以膨胀为一个拟商群．     

New Order Relations in Set Optimization

In this paper we study a set optimization problem (SOP), i.e. we minimize a set-valued objective map F, which takes values on a real linear space Y equipped with a pre-order induced by a convex cone K. We introduce new order relations on the power set P(Y)\mathcal{P}(Y) of Y (or on a subset of it), which are more suitable from a practical point of view than the often used minimizers in set optimization. Next, we propose a simple two-steps unifying approach to studying (SOP) w.r.t. various order relations. Firstly, we extend in a unified scheme some basic concepts of vector optimization, which are defined on the space Y up to an arbitrary nonempty pre-ordered set (Q,\preccurlyeq)(\mathcal{Q},\preccurlyeq) without any topological or linear structure. Namely, we define the following concepts w.r.t. the pre-order \preccurlyeq\preccurlyeq: minimal elements, semicompactness, completeness, domination property of a subset of Q\mathcal{Q}, and semicontinuity of a set-valued map with values in Q\mathcal{Q} in a topological setting. Secondly, we establish existence results for optimal solutions of (SOP), when F takes values on (Q,\preccurlyeq)(\mathcal{Q},\preccurlyeq) from which one can easily derive similar results for the case, when F takes values on P(Y)\mathcal{P}(Y) equipped with various order relations.     

序关系与0—1规划问题(下)

§ 9 集 合 组 装 问 题 以下,我们讨论如§5中所给出的准序。对于一个集 合XB_1~n,如果x=(x_1,x_2,…x_n)∈X,存在N={1,2,…,n}上的一个置换π使得 有x_(π(1))x_(π(2))…x_(π(n)),即 对于X是一个线性序,则称X是正则的。 相仿地,对于一个布尔或拟布尔函数f,也可建立准序:     

集值优化问题严格有效解的一、二阶最优性条件

首先定义了集值优化问题的m阶局部严格有效解并在赋范空间中研究了解的一些性质.在一定条件下,利用Dini导算子和支撑函数确立了m≥1阶严格有效解存在的充分必要条件.     

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...     

Finite and Infinite Order Differential Relations for Theta Functions

We give different linear and nonlinear differential relations on Jacobi theta functions with more emphasis on the nonlinear differential equation of the third order of Jacobi. We present different points of view with a special attention to the role played by the second order linear differential equations, and their link to the Riccati equation and the Schwarzian equation. We also study an identity for theta functions resulting from the action of certain infinite order differential operators.     

r-锥和严格r-锥

引入有限维向量空间的r-锥和严格r-锥的概念,证明了r-锥是一类闭锥,严格r-锥是一类开锥。并且,研究了r-锥和严格r-锥与较多锥、严格较多锥及它们的闭包和内部之间的关系。     

Weakly Strict Regular Semigroups

Weakly strict regular semigroups WS represent a generalization of strict regular semigroups. For the intersection of WS with some usual e-varieties of regular semigroups, such as left regular orthodox semigroups and similar e-varieties V, we provide WS ⋂ V with a basis of identities and forbidden semigroups. The latter, by exclusion, characterize the given e-variety. We do this also for WS. Coupled with some results of Hall, Churchill and Trotter, we characterize in this way also the e-varieties of completely regular semigroups as well as regular semigroups which are locally completely regular. The e-varieties studied are depicted in a diagram.     

Strict and bistrict plus-operators

We consider the theory of operators in spaces with indefinite metric. Strict plus-operators acting between two Krein spaces are considered. A construction showing that, under certain conditions, a strict plus-operator can be considered as a bistrict plus-operator without loss of generality is given.     

Semilocal Convergence Analysis of an Iteration of Order Five Using Recurrence Relations in Banach Spaces

Mediterranean Journal of Mathematics - Semilocal convergence for an iteration of order five for solving nonlinear equations in Banach spaces is established under second-order Fréchet...     

Strict 2-threshold graphs

A graph G is called a strict 2-threshold graph if its edge-set can be partitioned into two threshold graphs T₁ and T₂ such that every triangle of G is also a triangle of T₁ or of T₂. We indicate a polynomial-time algorithm to recognize these graphs and characterize them by forbidden configurations.