首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 62 毫秒
1.
设G是一个图,g,f是定义在V(G)上的非负整数函数,如果对G中任意n个顶点的集合D,G-D有(g,fd)-因子,则称G是(g,f,n)-可消去图。本文给出了二分图G是(g,f,n)-可消去图的一个充要条件,并且研究了(g,f,n)-可消去图的一些性质。  相似文献   

2.
设G是一个简单图,f:V(G)→(1,3,5....),如何对G的任意n对集M,G-V(M)有一个(1,f)-奇因子,则称图G存在n-可扩充的(1,f)-奇因子,本文主要对n-可扩充图成立的一些结果进行了改进,证明了这些结果在有n-可扩充的(1,f)-奇因子的图中也成立。  相似文献   

3.
设G是一个简单图,f:V(G)→{1,3,5,…},如果对G的任意n对集M,G—V(M)有一个(1,f)一奇因子,则称图G存在n-可扩充的(1,f)一奇因子.本文主要对n-可扩充图成立的一些结果进行了改进,证明了这些结果在有n-可扩充的(1,f)一奇因子的困中也成立.  相似文献   

4.
设g和f是定义在二分图G的顶点集V(G)上的两个整数值函数且对每个x∈V(G)有g(x)≤f(x).证明了若H是二分图G的任一m-星,则G有一个(g,f)-因子分解与H正交的充要条件是G为一个(mg,mf)-图.  相似文献   

5.
设G为具有n个顶点的图,Zn为模n整数加群.从G的顶点集到Zn的任一双射f称为G的一个循环标号.f的循环带宽Bc(G,f)定义为max(u,v)∈E(G)d(f(u),f(v)),其中对任意x,y∈Zn,d(x,y)=min{|x-y|,n-|x-y|}.G的循环带宽Bc(G)是指对G的所有循环标号f的循环带宽的最小值.借鉴关于带宽的已有结论,深入讨论循环带宽的Harper型下界,所得结果将有助于确定一些特殊图的循环带宽  相似文献   

6.
设G是具有n个顶点的2-连通简单MCD图,f2(n)表示G的边数.本文证明了当n≥8时,其中xm=um-2um-5,um是Fibonacci数.  相似文献   

7.
设G是具有n个顶点的2-连通简单MCD图,f2(n)表示G的边数.本文证明了当n≥8时,其中xm=um-2um-5,um是Fibonacci数.  相似文献   

8.
K1,n—free图的f—因子   总被引:2,自引:0,他引:2  
图G称为K1,n-free,若图G不包含同构于K1,n的导出子图。设f(x)是定义在V(G)上的非负整数函数,G的一个支撑子图F称为G的一个f-因子,若对任意的v∈V(G)有dF(v)=f(v),对K1,n-free图存在f-因子涉及到最小度条件进行了研究,得到了一个充分条件。有关定理为本定理的特例。  相似文献   

9.
设G是有n个顶点的简单图.f:V(G)→{1,2,…,n}是双射。定义S(G)=minSf(G),其中Sf(G)=∑/∈E|f(u)-f(v)|,称S(G)为G的带宽和,得到了树及无三角形图的带宽和上界。  相似文献   

10.
设G为具有n个顶点的图,Zn为模n整数加群。从G的顶点集到Zn的任一双射f称为G的一个循环标号。f的循环带宽Bc(G,f)定义为maxd(f(u),f(v),其中对任意x,y∈Zn,d(x,y)=min{|x-y|,n-|x-y|}。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

14.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

15.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

16.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

17.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

18.
For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the  相似文献   

19.
Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of  相似文献   

20.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号