关于图运算的测地数

对于图G(或有向图D)内的任意两点u和v,u-v测地线是指在u和v之间(或从u到v)的最短路.I(u;v)表示位于u-v测地线上所有点的集合,对于SV(G)(或V(D)),I(S)表示所有I(u,v)的并,这里u,v∈S.G(或D)的测地数g(G)(或g(D))是使I(S)=V(G)(或I(S)=V(D))的点集S的最小基数.G的下测地数g-(G)=min狖g(D):D是G的定向图狚,G的上测地数g+(G)=max狖g(D):D是G的定向图狚.对于两个图G和H,u∈V(G)和v∈V(H),在u和v之间加一条边,然后再收缩这条边uv所得的图,记为GuHv.本文主要研究图GuHv的测地数和上(下)测地数.     

树图的外围维纳指标的下界

设G=(V,E)为简单连通图.对v∈V(G),顶点v的离心率ε(v)=max{d(u,v)│u∈V(G)}, d(u,v)为图G中顶点u,v间的距离.图G的直径为d(G)=max{ε(v)│v∈V(G)}.外围顶点集P(G)指图G中满足ε(v)=d(G)的所有v=V(G).图G的外围维纳指标为■.首先讨论了当树图T的外围顶点个数确定时,它的第二下界;然后讨论了当树图T的顶点数目确定时,其对应的PW(T)的最小值,及达到其最小值的极图.     

联树模型在亏格等式证明中的应用

应用联树模型,把图浸入平面,获得这个图的关联曲面,从而获得这个图的嵌入曲面的亏格.应用这个方法,我们证明了2个著名的亏格等式.第1如果e是图G的一条割边,G-e有2个分支G1,G2,那么,g(G1) g(G2)=g(G).其中g(G)表示图G的亏格.第2用H*vK表示图H与K在点v处的结合,即V(H)∩V(K)=v,E(H)∩E(K)=φ.γ(G)表示图G的最小可定向亏格.那么,γ(H*vK)=γ(H) γ(K).     

围长至少为6的曲面图的列表单射染色

图G的一个点染色称为单射染色,如果任何两个有公共邻点的顶点染不同的颜色.一个图G称为单射k-可选择的,如果对于顶点V(G)的任何一个大小为k的允许颜色列表L,都存在一个单射染色φ,使得对于v∈V(G),有φ(v)∈L(v).使得G为单射k-可选择的最小k,称为G的列表单射染色数,记作χ_i~l(G).设G是最大度为Δ,围长为g的可嵌入到欧拉示性数χ(Σ)≥0的曲面Σ的一个图.证明了若Δ≥7且g≥6,则χ_i~l(G)≤Δ+3.     

图的稳定数和(g,f)-因子（英文）

设f,g:V→Z是定义在顶点集V上的两个整数函数.(g,f)-因子是图G的一个生成子图H使得g(v)≤dH(v)≤f(v)对每个顶点v∈V成立.本文给出存在(g,f)-因子的一个充分条件.     

伞状树的奇强协调性

设G=V,E是一个简单图,若存在一个映射f:V(G)→{0,1,2,…,2|E|-1}满足(1)对任意的u,v∈V,若u≠v,则f(u)≠f(v);(2)对任意的e1,e2∈E,若e1≠e2则g(e1)≠g(e2),此处g(e)=f(u)+f(v),e=uv,且{g(e)|e∈E}={1,3,5,…,2|E|-1},则称G是奇强协调图,f为G的奇强协调标号,讨论了一类树的奇强协调性.     

2-连通图的周长与围长

设G是具有围长 g≥5 的n阶2-连通简单图,若对于任意 u,v∈V(G),且d(u,v)=2,都有 max{d(u),d(v)}≥b,则G的周长为     

关于简单图的周长与围长

设G是具有围长g≥4 和最小度δ≥2 的简单图。若对于任意 u,v∈V(G),d(u,v)=2,都有 max{d(u),d(v)}≥b(≥δ),则 G的周长为     

固定直径树的距离平方和问题

定义图G中所有点对间的距离的平方和为S(G)=∑uv∈VGd2G(u,v)=1/2∑v∈VGLG(v),其中dG(u,v)为图G中任意顶点u,v之间的距离,LG(v)表示图G中点v到其它点的距离的平方和。在所有直径为d的n顶点树中分别确定使S(G)最小和第二小的树。     

2-连通图的最长圈

设 G是具有围长 g≥5 的 n 阶 2-连通简单图,P=v_1v_2…v_t 是 G的一条最长道路。若λ=min{d(u)+d(v)|u,v∈V(G),uv∈E(G)},δ~*=min{d(v_1),d(v_t)},则G的最长圈为:其中.δ= min{d(v)|v∈V(G)}。     

Markedness and its Interpretation in Language Use

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.     

Features of Women's language

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.     

低渗透非均质砂岩油藏启动压力梯度研究

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。     

On Tragic Consciousness In The Works By Ernest Hemingway

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.     

Achieving Unusual States of Matter Under High Pressure

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-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

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-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

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     

Call for Papers

<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     

Journal of Donghua University ( English Edition) Contents of Volume 31

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Brief Introduction to “Journal of Jilin University( Science Edition) ”

<正>"Journal of Jilin University(Science Edition)"is a comprehensive academic journal in the fields of science sponsored by Jilin University and administrated by the Ministry of Education of the Peoples Republic of China.The journal started publication in 1955.The original name at starting publication was"Journal of Natural Science of Northeast People University",which was changed into"Acta Scientiarum Naturalium Universitatis Jilinensis"in 1958 owing to the name change of the university.The present journal name has