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1.
一个有向图D称为本原有向图,若存在某自然数k,使D中任一点u到任一点v都有长为k之途径。若D是一个对称有向图,则D是本原的当且仅当D对应的无向图G连通且至少包含一个奇圈。本文研究最小奇圈长为r的n阶对称本原有向图,完全刻划了第一类广义本原指数集,并部分地解决了第三类广义本原指数集的刻划问题。  相似文献   

2.
对称本原有向图的重上广义本原指数   总被引:1,自引:1,他引:1  
一个有向图D称为本原有向图,若存在某自然数K,使D中任一点u到任一点u都有长为k之途径。本文中,我们决定具有最小奇圈长r的n阶对称本原有向图的第k第上广义本原指数的最大数。  相似文献   

3.
对称本原有向图的广义本原指数集   总被引:3,自引:0,他引:3  
本文证明了全体n阶对称本原有向图的第k个第一类(1≤k<n-1)、第二类(1≤k≤n-1)和第三类(2≤k≤n-1)广义本原指数的指数集分别是{1,2,…,n-2+k}和{1,2,…,2(n-k)},其中「a]表不小于a的最小整数,[b]表不大于b的最大整数。  相似文献   

4.
A digraph G is called primitive if there ekists a positive integer k such that there isa walk of length k from u to v for each ordered pair of not necessarily distinct vertices uand v. The smallest such k is called the exponent of G, denoted by γ(G). Exponents forprimitive digraphs have been studied extensively due to their intrinsic importance in graphtheory, combinatorics, matrix theory, and their applications in communication problems. Asa generalization of exponents, Brualdi and Liu[1] …  相似文献   

5.
一个有向图D称为本原的,如果存在某个正整数k,使得对于D中的任一点x到任一点y都有长为k的途径,这样的正整数k中的最小者称为D的本原指数,作为本原指数概念的推广,R.A.Brualdi和柳柏濂于1990年引入了本原有向图的广义本原指数的新概念,本文给出了对称本原图的集指数的一些性质,并对本原简单图的广义上指数的极图进行了完全刻划。  相似文献   

6.
7.
陈振龙  刘三阳 《数学杂志》2003,23(1):102-106
本文讨论了广义Wiener过程的极性,得到了其极性的两个充分条件,它类同于Brown运动的性质。  相似文献   

8.
本文研究了围长为2的n阶本原极小强连通有向图的1-指数集,证明了:当n(≥4)为偶数时,E(1)={4,5,6,7,…,2n-4),无缺数段。  相似文献   

9.
对称本原有向图广义重上指数的极图刻划   总被引:2,自引:0,他引:2  
邵燕灵  高玉斌 《数学学报》2000,43(3):427-434
一个有向图D称为本原有向图,若存在某自然数k,使D中任一点u到任 一点v都有长为k之途径.若D是一个对称有向图,则D是本原的当且仅当D对 应的无向图连通且至少包含一个奇圈。文[2]给出了具有最小奇圈长r的n阶对称本 原有向图广义k重上指数的最大数.本文将在此基础上,给出其极图的完全刻划.  相似文献   

10.
1IntroductionandMainResultsItiswellknownthatwhenp'--4q>0,secondorderautonomoussystemhastwocharacteristicexponentsfsothefollowingpropositionsareobvious.Proposition1Assumeq<0,then(1.1)hastwocharacteristicexponentswithoppositesigns.Proposition2Assumeq>0andp'…  相似文献   

11.
In this paper, a second order linear differential equation is considered, and an accurate estimate method of characteristic exponent for it is presented. Finally, we give some examples to verify the feasibility of our result.  相似文献   

12.
THE SECOND EXPONENT SET OF PRIMITIVE DIGRAPHS   总被引:2,自引:0,他引:2  
51.IntroductionandNotationsLetD=(V,E)beadigraphandL(D)denotethesetofcyclelengthsofD.ForuEVandintegeri21,letfo(u):={vEVIthereedestsadirectedwalkoflengthifromutov}.WedelveRo(u):={u}.Letu,vEV.IfN (v)=N (v)andN--(v)=N--(v),thenwecanvacopyofu.LotDbeaprimitivedigraphand7(D)denotetheexponentofD.In1950,H.WielandtI61foundthat7(D)5(n--1)' 1andshowedthatthereisapiquedigraphthatattainsthisbound.In1964,A.L.DulmageandN.S.Mendelsohn[2]ObservedthattherearegapsintheexponentsetEd={ry(D)IDEPD.}…  相似文献   

13.
This paper deals with the Neumann problem for a class of semilinear elliptic equations -△u u =|u|2*- 2u μ|u|q- 2u in Ω, u/r=|u|s*- 2u on Ω, where 2* = 2N/N- 2,s*=2(N- 1)/N-2, 1 < q < 2, N ≥ 3, μ> 0,γ denotes the unit outward normal to boundaryΩ. By variational method and dual fountain theorem, the existence of infinitely many solutions with negative energy is proved.  相似文献   

14.
非凸半定规划的广义Fakars引理及最优性条件   总被引:1,自引:0,他引:1  
1引言在本文中,我们用(?),S~n,S_ ~n分别表示有限维向量空间,n阶对称矩阵空间及n阶半正定矩阵锥.我们考虑如下形式的非凸半定规划问题:  相似文献   

15.
《代数通讯》2013,41(2):859-867
Abstract

The question, posed in Crawley and Jónsson (Crawley, P., Jónsson, B. (1964). Refinements for infinite direct decompositions of algebraic systems. Pacific J. Math. 14:797–855), whether the finite exchange property implies the unrestricted exchange property for any modules, is still open. In this note we obtain the equivalence of the finite exchange property and the unrestricted exchange property for the class of modules whose endomorphism rings are Abelian.  相似文献   

16.
《Optimization》2012,61(2):353-399
Abstract

Both parametric and parameter-free stationary-point-type and saddle-point-type necessary and sufficient optimality conditions are established for a class of nonsmooth continuous-time generalized fractional programming problems with Volterra-type integral inequality and nonnegativity constraints. These optimality criteria are then utilized for constructing ten parametric and parameter-free Wolfe-type and Lagrangian-type dual problems and for proving weak, strong, and strict converse duality theorems. Furthermore, it is briefly pointed out how similar optimality and duality results can be obtained for two important special cases of the main problem containing arbitrary norms and square roots of positive semidefinite quadratic forms. All the results developed here are also applicable to continuous-time programming problems with fractional, discrete max, and conventional objective functions, which are special cases of the main problem studied in this paper.  相似文献   

17.
In this paper we shall give a simple and easy method to estimate the characteristic exponents for a class of second order linear different equation with periodic coefficient which frequently occurs in application.  相似文献   

18.
We consider the quadrilateral Q1 isoparametric element and establish an optimal error estimate in H^1 norm for the interpolation operator under a weaker mesh condition which admits anisotropic quadrilaterals and allows the quadrilateral to become a regular triangle in the sense of maximum angle condition [5, 11].  相似文献   

19.
1. Introduction and PreliminariesThe set of all m x n comPlex matrices of rank r is denoted by cy". By I we denote anappropriate ideniity matrix. Also, n(A) denotes the trace of a square matriX A. By n(A) andN(A) are denoted the range and the null space of A, respectively Finally ad(A) and det(A)denote the adoint of the matris A and the determinant of A, respectivelyFOr any matrix A E crxn consider the following equations in X:(1) AXA=A, (2) XAX=X, (3) (AX)*=AX, (4) (XA)*=XAand…  相似文献   

20.
In this article, we study the quasilinear elliptic problem involving critical Hardy Sobolev exponents and Hardy terms. By variational methods and analytic techniques, we obtain the existence of sign-changing solutions to the problem.  相似文献   

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