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1.
剩余格与正则剩余格的特征定理   总被引:48,自引:1,他引:47       下载免费PDF全文
裴道武 《数学学报》2002,45(2):271-278
本文进一步研究了具有广泛应用的一类模糊逻辑代数系统-剩余格,并引入了正则剩余格的概念,对剩余格与正则剩余格的定义进行了讨论,给出了剩余格与正则剩余格的特征一理,其中包含剩余格与正则剩余格的等式特征,从而这两个格类都构成簇。本文还讨论了剩余格与正则剩余格公理系统的独立性,以及它们与相近代数结构的关系。  相似文献
2.
Axiomatics for fuzzy rough sets   总被引:39,自引:0,他引:39  
A fuzzy T-rough set consists of a set X and a T-similarity relation R on X, where T is a lower semi-continuous triangular norm. We generalize the Farinas-Prade definition for the upper approximation operator of a fuzzy T-rough set (X, R); given originally for the special case T = Min, to the case of arbitrary T. We propose a new definition for the lower approximation operator of (X,R). Our definition satisfies the two important identities and , as well as a number of other interesting properties. We provide axiomatics to fully characterize those upper and lower approximations.  相似文献
3.
非奇异H矩阵的实用充分条件   总被引:34,自引:1,他引:33       下载免费PDF全文
干泰彬  黄廷祝 《计算数学》2004,26(1):109-116
In this paper, several practical sufficient conditions for nonsinguular H-matrices are obtained by comparing the elements of a matrix. Advantage of results obtained is illustrated by a numerical example.  相似文献
4.
E-Convex Sets, E-Convex Functions, and E-Convex Programming   总被引:31,自引:0,他引:31  
A class of sets and a class of functions called E-convex sets and E-convex functions are introduced by relaxing the definitions of convex sets and convex functions. This kind of generalized convexity is based on the effect of an operator E on the sets and domain of definition of the functions. The optimality results for E-convex programming problems are established.  相似文献
5.
Permanence of population growth models with impulsive effects   总被引:24,自引:0,他引:24  
This paper establishes criteria for permanence of populations which undergo impulsive effects at fixed times between intervals of continuous evolution governed by a differential system. It is also shown that suitable impulses may prevent the extinction or unbounded growth of populations whose evolutions are otherwise governed solely by a differential system. Examples are provided to demonstrate the application of the results obtained.  相似文献
6.
Whether or not the general asymmetric variational inequality problem can be formulated as a differentiable optimization problem has been an open question. This paper gives an affirmative answer to this question. We provide a new optimization problem formulation of the variational inequality problem, and show that its objective function is continuously differentiable whenever the mapping involved in the latter problem is continuously differentiable. We also show that under appropriate assumptions on the latter mapping, any stationary point of the optimization problem is a global optimal solution, and hence solves the variational inequality problem. We discuss descent methods for solving the equivalent optimization problem and comment on systems of nonlinear equations and nonlinear complementarity problems.  相似文献
7.
Generalized B-vex functions and generalized B-vex programming   总被引:19,自引:0,他引:19  
A class of functions called pseudo B-vex and quasi B-vex functions is introduced by relaxing the definitions of B-vex, pseudoconvex, and quasiconvex functions. Similarly, the class of B-invex, pseudo B-invex, and quasi B-invex functions is defined as a generalization of B-vex, pseudo B-vex, and quasi B-vex functions. The sufficient optimality conditions and duality results are obtained for a nonlinear programming problem involving B-vex and B-invex functions.The first author is thankful to the Natural Science and Engineering Research Council of Canada for financial support through Grant A-5319. The second author is grateful to the Faculty of Management, University of Manitoba for the financial support provided for her visit. The authors are thankful to Prof. R. N. Kaul, Department of Mathematics, Delhi University for his constructive criticism of the paper.  相似文献
8.
A survey of retrial queues   总被引:18,自引:0,他引:18  
We present a survey of the main results and methods of the theory of retrial queues, concentrating on Markovian single and multi-channel systems. For the single channel case we consider the main model as well as models with batch arrivals, multiclasses, customer impatience, double connection, control devices, two-way communication and buffer. The stochastic processes arising from these models are considered in the stationary as well as the nonstationary regime. For multi-channel queues we survey numerical investigations of stationary distributions, limit theorems for high and low retrial intensities and heavy and light traffic behaviour.  相似文献
9.
Proper efficiency with respect to cones   总被引:17,自引:0,他引:17  
Strict separation by a cone is used here to redefine proper efficiency. Two versions of the properness, which unify and generalize known definitions, are presented. Necessary and sufficient conditions for the existence of the set of properly efficient decisions and characterization of this set in terms of the supports of the decision set are given.The research was done while the author was a visiting professor at the University of British Columbia, Vancouver, British Columbia, Canada.  相似文献
10.
Wiener Index of Hexagonal Systems   总被引:17,自引:0,他引:17  
The Wiener index W is the sum of distances between all pairs of vertices of a (connected) graph. Hexagonal systems (HS's) are a special type of plane graphs in which all faces are bounded by hexagons. These provide a graph representation of benzenoid hydrocarbons and thus find applications in chemistry. The paper outlines the results known for W of the HS: method for computation of W, expressions relating W with the structure of the respective HS, results on HS's extremal w.r.t. W, and on integers that cannot be the W-values of HS's. A few open problems are mentioned. The chemical applications of the results presented are explained in detail.  相似文献
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