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1.
设G是一个图,具有顶点集V(G)和边集E(G).设g和f是定义在V(G)上的整数值函数且对每个x∈y(G)有g(x)≤f(x).本文证明了如下的结果:若G是一个(mg+kr,mf-kr)一图,且对每个x∈V(G)有g(x)≥r-1,H和G的任意给定的有kr条边的子图,则G中含有一个子图R,使R有(g,f)-因子分解r-正交于H,其中m,k和r是正整数且k〈m.  相似文献   

2.
图的1-因子、f-因子和(g,f)-因子   总被引:5,自引:0,他引:5  
设G是一个图且有一个1-因子F,g和f是定义在V(G)上的非负整数值函数且对每个X∈V(G)有g(X)<f(X)≤dG(x),且f(v(G))为偶数.(i)若对每个xy∈F有f(x)=f(y)且G-{x,y}有一个(g,f)-因子,则G有一个(g,f)-因子;(ii)若对每个xy∈F有f(X)=f(y)且G-{X,y}有f-因子,则G有f-因子.  相似文献   

3.
图的符号星k控制数   总被引:3,自引:0,他引:3  
引入了图的符号星k控制的概念.设G=(V,E)是一个图,一个函数f:E→{-1,+1},如果∑e∈E[v]f(e)≥1对于至少k个顶点v∈V(G)成立,则称f为图G的一个符号星k控制函数,其中E(v)表示G中与v点相关联的边集.图G的符号星k控制数定义为γkss(G)=min{∑e∈Ef(e)|f为图G的符号星k控制函数}.在本文中,我们主要给出了一般图的符号星k控制数的若干下界,推广了关于符号星控制的一个结果,并确定路和圈的符号星k控制数.  相似文献   

4.
1问题的提出在中学数学教学时,经常会遇到类似这样的问题:函数y=sinx(x>0)是不是周期函数?要回答这个问题,我们还得从周期函数的定义谈起.2关于周期函数的定义关于周期函数的定义,我们常见的有如下两种:定义1设f(X)是定义在某数集M上的函数,若有在一常数T(≠0),具有性质;(i)对于任回x∈M,有±T∈M;(ii)对于任何x∈M,有f(x+T)=f(x),那么称f(x)为集M上的周期函数.常数T称为f(x)的一个周期.定义2对于函数y=f(x)的定义域内的任意一个x的值,若存在一个非零常数T,使得f(x+T)=f(x)恒成立,则…  相似文献   

5.
广义凸函数性质初探   总被引:4,自引:0,他引:4  
设函数f(x)在区间I上有定义.如果对于任意x_1、x_2∈I和t∈(0,1)有则说f(x)在I上为下凸的.如果对于任意x_1、x_2∈I和t∈(0,1)有则说f(x)在I上为上凸的,如果对于一切t∈(0,1),(1)式((2)式)中的等式仅当x_1=x_2时成立,则说f(x)在I上为严格下凸(严格上凸)的.显然,如果f(x)在I上是上凸的,则-f(x)在I上就是下凸的.为此,以下我们着重讨论下凸函数由[1],若函数f(x)在区间I上连续且对任意x_1、x_2∈I成立,则f(x)在I上是下凸的.对于凸函数,我们有著名的Jensen不等式:命题1设f(x)是区间…  相似文献   

6.
禹继国  刘桂真 《应用数学》2003,16(1):126-129
设G是一个二分图具有顶点集V(G)和边集E(G)。设g和f是定义在V(G)上的两个正整值函数使对任意的x∈V(G)有g(x)≤f(x),G的一个(g,f)-因子H是G的一个生成子图满足g(x)≤dH(x)≤f(x)。若图G本身是一个(g,f)-因子,则称G是一个(g,f)-图。本文得到一个(mg,mf)-图具有特殊性质的(g,f)-因子的充分条件,从而推广了文献[6]中的一个结果。  相似文献   

7.
完全图全符号控制数的较小上界和下确界   总被引:2,自引:0,他引:2  
设图G=G(V,E),令函数f∶V∪E→{-1,1},f的权w(f)=∑x∈V∪Ef[x],对V∪E中任一元素,定义f[x]=∑y∈NT[x]f(y),这里NT[x]表示V∪E中x及其关联边、邻点的集合.图G的全符号控制函数为f∶V∪E→{-1,1},满足对所有的x∈V∪E有f[x]1,图G的全符号控制数γT(G)就是图G上全符号控制数的最小权,称其f为图G的γT-函数.本文得到了完全图全符号控制数的一个较小上界和下确界.  相似文献   

8.
Riesz函数演算的Lipschitz性质   总被引:1,自引:0,他引:1  
曹怀信  陈峥立 《数学学报》2007,50(2):319-324
设A是具有单位的复Banach代数,Ω为复平面C上的一个区域,γ是复平面上的任一可求长的封闭曲线且其内部区域ins(γ)Ω,证明了存在A的子集A_δ~γ,使得对于Ω上的任一解析函数f,Riesz函数演算f:xf(x)是从A_δ~γ到A中的Lipschitz映射即f∈L~1(A_δ~γ,A)且其Lipschtiz常数(L_1(f)■M_f(γ)Γ)/(2πδ~2).作为这一结果的应用,研究了算子值的根式函数TT~(1/m)及绝对值函数T|T|的Lipschitz性质.最后,证明了:若f为一个复值整函数,则对任一非空有界集EA,有f∈L~1(E,A).  相似文献   

9.
设G=(V,E)是一个图,一个函数f:V→{-1,+1}如果满足Σv∈N[υ]f(ν)≥1对于每个点u∈V成立,则称f为图G的一个符号控制函数,图G的符号控制数γs(G)定义为γs(G)=min{Σv∈vf(v)|f为图G的符号控制函数},类似地,可定义图G的上符号控制数Γs(G).研究了几类特殊图的符号控制问题,获得了完全l等部图和乘积图P_3×P_n的符号控制数,并确定了P_2×P_n和P_3×P_n的上符号控制数.  相似文献   

10.
题34 我们把y=x^a(a∈Q)叫做幂函数.幂函数y=x^a(a∈Q)的一个性质是:当a〉0时,在(0,+∞)上是增函数;当a〈0时,在(0,+∞)上是减函数.设幂函数f(x)=x^n(n≥2,n∈N^*).  相似文献   

11.
12.
Schr(o)dinger operator is a central subject in the mathematical study of quantum mechanics.Consider the Schrodinger operator H = -△ V on R, where △ = d2/dx2 and the potential function V is real valued. In Fourier analysis, it is well-known that a square integrable function admits an expansion with exponentials as eigenfunctions of -△. A natural conjecture is that an L2 function admits a similar expansion in terms of "eigenfunctions" of H, a perturbation of the Laplacian (see [7], Ch. Ⅺ and the notes), under certain condition on V.  相似文献   

13.
14.
正Applied Mathematics-A Journal of Chinese Universities,Series B(Appl.Math.J.Chinese Univ.,Ser.B)is a comprehensive applied mathematics journal jointly sponsored by Zhejiang University,China Society for Industrial and Applied Mathematics,and Springer-Verlag.It is a quarterly journal with  相似文献   

15.
正Journal overview:Journal of Mathematical Research with Applications(JMRA),formerly Journal of Mathematical Research and Exposition(JMRE)created in 1981,one of the transactions of China Society for Industrial and Applied Mathematics,is a home for original research papers of the highest quality in all areas of mathematics with applications.The target audience comprises:pure and applied mathematicians,graduate students in broad fields of sciences and technology,scientists and engineers interested in mathematics.  相似文献   

16.
A cumulative-capacitated transportation problem is studied. The supply nodes and demand nodes are each chains. Shipments from a supply node to a demand node are possible only if the pair lies in a sublattice, or equivalently, in a staircase disjoint union of rectangles, of the product of the two chains. There are (lattice) superadditive upper bounds on the cumulative flows in all leading subrectangles of each rectangle. It is shown that there is a greatest cumulative flow formed by the natural generalization of the South-West Corner Rule that respects cumulative-flow capacities; it has maximum reward when the rewards are (lattice) superadditive; it is integer if the supplies, demands and capacities are integer; and it can be calculated myopically in linear time. The result is specialized to earlier work of Hoeffding (1940), Fréchet (1951), Lorentz (1953), Hoffman (1963) and Barnes and Hoffman (1985). Applications are given to extreme constrained bivariate distributions, optimal distribution with limited one-way product substitution and, generalizing results of Derman and Klein (1958), optimal sales with age-dependent rewards and capacities.To our friend, Philip Wolfe, with admiration and affection, on the occasion of his 65th birthday.Research was supported respectively by the IBM T.J. Watson and IBM Almaden Research Centers and is a minor revision of the IBM Research Report [6].  相似文献   

17.
Résumé On décrit toutes les feuilles des laminations minimales dont un ensemble résiduel de feuilles ont 2 bouts.   相似文献   

18.
We develop a theory of downward sets for a class of normed ordered spaces. We study best approximation in a normed ordered space X by elements of downward sets, and give necessary and sufficient conditions for any element of best approximation by a closed downward subset of X. We also characterize strictly downward subsets of X, and prove that a downward subset of X is strictly downward if and only if each its boundary point is Chebyshev. The results obtained are used for examination of some Chebyshev pairs (W,x), where ∈ X and W is a closed downward subset of X  相似文献   

19.
In this paper, the author establishes the boundedness of multilinear operators on weighted Herz spaces and Herz-type Hardy spaces. The author also obtains their weak estimates on endpoints. As a special case, the conclusions may lead to the weighted estimates for multilinear Calderon-Zygmund operators.  相似文献   

20.
In this paper we present a generalized quantitative version of a result due to M. Revers concerning the exact convergence rate at zero of Lagrange interpolation polynomial to f(x) = |x|α with on equally spaced nodes in [-1, 1].  相似文献   

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