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1.
设X是一个v元点集,A是循环有序的k元子集簇.一个完全Mendelsohn设计,记为(v,k,λ)-PMD,是二元组(X,A),使得X中每个有序点对恰好t间隔地出现在λ个区组中.若一个区组恰有u个区组与之不交,则称之为βu区组.本文证明了共有141个不同构具有β1型区组的(12,4,1)-PMD.  相似文献   

2.
高源 《科学技术与工程》2006,6(22):3536-3541
令v与λ为正整数,K为正整数集。一个(v,K,λ)-Mendelsohn设计(简写为(v,K,λ)-MD)是一个对子(X,B),其中,X是一个v元集合(称之为点集),B是由X中k-子集(称之为区组)所组成的集合,其中k∈K且所含元素是循环有序的,使得X中任意有序对恰相邻出现在、B中的A个区组中。如果对于所有t=1,2,…,r,X中任意有序对均恰以t-间隔的形式在,B中出现A次,则称其为r-完美设计,并且简记为r-完美(v,K,λ)-MD。主要讨论2-完美(v,{3,k},λ)-Mendelsohn设计的存在性,其中k取自集合{4,5,6,7}。  相似文献   

3.
一个Mendelsohn设计MD(v,k,λ)称为是自反的,记为SCMD=(v,k,λ)=(X,B,f),如果存在从(X,B)到(X,B-1)的同构映射f,B-1={B-1;B∈B},其中若B=则B-1=.当λ=1时记作k-SCMD(v).一个{k1,k2}-SCMD(v)称为是自反强制Mendelsohn设计,记作{k1,k2}-SCMMD(v),若{k1,k2}-SCMD(v)中区组长度至少有一个k1和一个k2.该文给出了{3,4}-SCMD(v)和{3,4}-SCMMD(v)的存在性.  相似文献   

4.
设S是连通图G中的一个边子集。若G-S不连通且它的每个连通分支的阶至少为k,则称S是G的一个k限制边割。图G的最小k限制边割的边数称为G的k限制边连通度,记为λk(G).义ζk(G)=min{|[X,X]|∶|X|=k,G[X]连通},其中X=V(G)\X.若λk(G)=ζk(G),则称G是λk-最优的。如果图G的每个最小k限制边割都孤立了一个k阶连通子图,那么称G是超级-λk的。设k是一个不小于2的正整数且G是一个阶不小于2庇的图。本文证明了若对于G中任意一对不相邻顶点u,v都有d(u)+d(v)≥ν+2k-4且G不属于一类特殊图,则G是λk-最优的。最后,给出了图是超级-λk的一个充分条件。  相似文献   

5.
设S是连通图G中的一个边子集。若G S不连通且它的每个连通分支的阶至少为k,则称S是G的一个k限制边割。图G的最小k限制边割的边数称为G的k限制边连通度,记为λκ(G)。定义ξκ(G)=min{|[X,X]|:|X|=k,G[X]连通},其中X=V(G)\X。若λk (G)=ξk(G),则称G是极大k限制边连通的。设G是一个围长至少为5的λ3 连通图。本文证明了若G中不存在5个点u1,u2,v1,v2,v3使得d(ui,vj)≥3(i=1,2;j=1,2,3),则G是极大3限制边连通的。  相似文献   

6.
本文证明了若G为一个k(k≥2)连通简单图,最小度为,δV(G)=n≥3,X 1,X 2,……,X k是顶点集合V的子集,X=X1∪X2∪…∪Xk,且对于Xi(i=1,2……k)中任意两个不相邻点u,v,都有N(u)∪N(v)≥n-δ,则X在G中可圈。并给出几个相关推论.  相似文献   

7.
如果从一个有向平衡不完全区组设计DB(k,λ;v)(X,B)到(X,β-1)之间存在一个同构映射f,则这个DB(k,λ;v)被称为自反的,记为SCDB(k,λ;v)(X,β,f),其中β-1={B-1:B∈B},当B=(x1,x2,…,xk-1,xk)时B-1=(xk,xk-1,…,x2,x1).本文主要证明了SCDB(4,λ;v)存在的充分必要条件是λ≡1,2(mod 3)时,v≡1(mod 3)且v≥4,(v,λ)≠(7,1);λ≡0(mod 3)时,v为≥4的任意整数.  相似文献   

8.
设v,k,λ都是正整数.一个(v,k,λ)-循环差集B={b_1,b_2,…,b_k}是k个不同的模v的剩余组成的集合,其中有对任何一个模v不同余0的数b,同余方程b_i-b_j≡b(mod v)都恰有λ组解,其中bi,bj都属于B.本文给出了(v,k,λ)-循环差集的一个必要条件,并计算出了阶为2和3的所有的循环差集.  相似文献   

9.
v阶加法群G上的(v,k,λ)差族为G的k元子集(基区组)族B={B_i:1≤i≤t},使得ΔB=∪_(B∈B)ΔB恰好覆盖G\0}中的每个元素λ次.若该区组集B中的区组互不相交,则称B为不相交差族,记为(v,k,λ)-DDF.关于k=3,4时(v,k,λ)-DDFs的存在性已经有部分结果.该文考虑(v,K,λ,Q)-DDF,并证明对于任意的素数p≡1(mod 18),存在平衡(p,{3,4},1)-DDF.  相似文献   

10.
给出了(b,v,r,k,λ)组态及(v,k,λ)组态的个数,r×n拉丁长方的个数,k-1个相互正交的n阶拉丁方组的个数的几个精确计算公式.并将(b,v,r,k,λ)及(v,k,λ)组态的存在及构造问题转化为判断和寻找一个数论问题的非负整数解的问题.  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.
<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   

20.
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