置换群的计算机算法

从电子计算机一诞生起人们就注意到,它不仅能进行具体的数值运算,还具备记忆、判断等功能,因而有可能被用来进行抽象的符号运算。随着计算机技术(包括硬件设备和软件系统)的发展,上述设想变成了现实。1960年首先出现了Neubuser借助计算机研究子群格的工作。尔后,计算机越来越多地被用于研究各种各样的代数结构,产生了众多的算法,以至形成了所谓的“计算代数(ComPutational Algebra)”。事实上,近年来确有不少重要成     

关于置换群中某些组合问题的计数公式

本文对于置换群中,恰具 l 个轮的置换个数,以及恰具 l 个轮换但无1—轮换的置换个数的计数问题,给出了一个明确而简洁的计算公式。这不论对有关问题的理论研究方面,还是实际应用都有其一定的意义。     

有极大次数的传递置换群

本文研究有有界运动的置换群,给出了非单位元恰有两个运动的有极大次数的传递置换群的结构和分类,推广了文献[1]的结果.     

一类仿射型本原非同步置换群的构造

同步置换群的研究是置换群理论中的一个前沿课题.通过在有限域上定义广义Paley图,来讨论这类图的团数(clique number)和色数(chromatic number)相等的条件.然后证明构造的广义Paley图和一类仿射群的轨道图同构,进而讨论这类仿射群的同步性.在此基础上给出一类本原非同步群的构造.     

关于高一学生"算法"学习情况的调查

从2004年9月份起，山东、广东、宁夏、海南四省（区）开始进行高中课标新课程实验．在新课程中，算法作为数学及其应用的重要组成部分，第一次成为高中数学必修课的内容，是数学3的一个主要部分．新增算法内容，既反映时代的要求，也反映我国古代数学重视计算的优良传统．算法教学有利于培养学生的逻辑思维能力，有利于学生理解构造性数学，为学生未来的学习特别是信息技术方面的学习提供支持．那么高中学生对算法的情感态度如何？     

关于BCK代数的模型论性质

This paper is devoted to the study of the logical properties of BCK algebras. For formalized BCK algebra theory T, it is proved that T is preserved under submodels and unions of chains; T is neither complete nor model complete, and hence there exist no built-in Skolem function. Moreover, the ultraproduct BCK algebras and the fuzzy ultraproduct of fuzzy subsets of BCK algebras were proposed by using the concept of ultrafilters with corresponding properties of fuzzy ideals discussed.     

Huang算法与Givens变换

本文讨论Ｈｕａｎｇ算法与Ｇｉｖｅｎｓ变换的关系．证明了Ｇｉｖｅｎｓ变换的乘积矩阵可由Ｈｕａｎｇ算法生成     

离散卷积的W变换算法

离散卷积的Ｗ变换算法曾泳泓（国防科技大学）ＣＯＭＰＵＴＩＮＧＤＩＳＣＲＥＴＥＣＯＮＶＯＬＵＴＩＯＮＳＢＹＷＴＲＡＮＳＦＯＲＭ￥ＺｅｎｇＹｏｎｇ－ｈｏｎｇ（ＮａｔｉｏｎａｌＵｎｉｖｅｒｓｉｔｙＯｆＤｅｆｅｎｓｅＴｅｃｈｎｏｌｏｇｙ）Ａｂｓｔｒａｃｔ：Ｆ...     

分形集的逼近算法

1引 言 设(X,d)是一个完备的距离空间,给定了X上的压缩映射组f_1,f_2,…,f_m记S={f_1,f_2,…,f_m},A是X的一个非空子集,如果具有性质A=∪f_i(A),则称A关于S是     

关于求线性规划初始可行基的生成算法

本文用反例证明了文「１」提出的求线性规划寝可行基的生成算法有错误,并给出了修正的生成算法。     

Generating a Random Signed Permutation with Random Reversals

Signed permutations form a group known as the hyperoctahedral group. We bound the rate of convergence to uniformity for a certain random walk on the hyperoctahedral group that is generated by random reversals. Specifically, we determine that O(n log n) steps are both necessary and sufficient for total variation distance and ℓ² distance to become small. This random walk arose as the result of an effort in molecular biology to model certain types of genome rearrangements.     

多阶段群体满意决策最优算法

针对多阶段群体满意决策问题,应用图论知识提出一种求解多阶段群体满意策略问题的最优算法.定义权ω为决策者对决策的总评价值,给出距离d和群体满意策略等概念.考虑实际情况中决策者的能力和认知的不同,赋予决策者变化的决策权重.将多阶段群体满意策略问题转换成在一个带有权向量的多部有向图中找权最大的路的问题.最后给出计算实例.     

A Parallel Randomized Algorithm for Finding a Maximal Independent Set in a Linear Hypergraph

We present a randomized parallel algorithm with polylogarithmic expected running time for finding a maximal independent set in a linear hypergraph.     

A Uniformly Quasiconformal Group Not Isomorphic to a Mobius Group

We explicitly give a group not isomorphic to any group of Mobius transformations of the three-dimensional sphere and acting quasiconformally on the three-dimensional sphere.     

A Sufficient and Necessary Condition for a Solvable Lie Algebra to Be Complete

In this paper,we give a sufficient and neccesary condition under which a solvable Lie algebra is complete.     

A Necessary Condition for Transitivity of a Finite Permutation Group

Suppose the group G is generated by permutations g₁, g₂, ...,g₈ acting on a set of size n, such that g₁g₂...g₈ is the identitypermutation. If the generator g_i has exactly c_i cycles (for1 i s), and G is transitive on , then n(s–2)– is a non-negative even integer. Thisis proved using an elementary graph-theoretic argument.     

An Efficient Branch-and-bound Algorithm for Finding a Maximum Clique with Computational Experiments

We present an exact and efficient branch-and-bound algorithm MCR for finding a maximum clique in an arbitrary graph. The algorithm is not specialized for any particular type of graph. It employs approximate coloring to obtain an upper bound on the size of a maximum clique along with an improved appropriate sorting of vertices. We demonstrate by computational experiments on random graphs with up to 15,000 vertices and on DIMACS benchmark graphs that in general, our algorithm decidedly outperforms other existing algorithms. The algorithm has been successfully applied to interesting problems in bioinformatics, image processing, design of quantum circuits, and design of DNA and RNA sequences for biomolecular computation.     

Conjugacy in Permutation Representations of the Symmetric Group

Although the conjugacy classes of the general linear group are known, it is not obvious (from the canonic form of matrices) that two permutation matrices are similar if and only if they are conjugate as permutations in the symmetric group, i.e., that conjugacy classes of S _n do not unite under the natural representation. We prove this fact, and give its application to the enumeration of fixed points under a natural action of S _n  × S _n . We also consider the permutation representations of S _n which arise from the action of S _n on ordered tuples and on unordered subsets, and classify which of them unite conjugacy classes and which do not.     

On the Orbit Sizes of Permutation Groups on the Power Set

We study the action of finite permutation groups of odd order on the power set of a set on which they act naturally, and establish a theorem that guarantees the existence of a lot of distinct orbit sizes in this action.1991 Mathematics Subject Classification: 20B05     

An Efficient Algorithm for Finding a Maximum Weight k-Independent Set on Trapezoid Graphs

The maximum weight k-independent set problem has applications in many practical problems like k-machines job scheduling problem, k-colourable subgraph problem, VLSI design layout and routing problem. Based on DAG (Directed Acyclic Graph) approach, an O(kn ²) time sequential algorithm is designed in this paper to solve the maximum weight k-independent set problem on weighted trapezoid graphs. The weights considered here are all non-negative and associated with each of the n vertices of the graph.