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 93 毫秒
1.
设G=(x,y)是一个二部图,若|X+=|Y|,则称G是一个均衡二部图,文章证明了设G是2n阶均衡二部图,对任意正整数k≥2,若n≥4k-3,且最小度δ(G)≥n+2(k-1)/2,则任给G的一个完美匹配M,G中存在一个包含M的所有边的恰含k个分支的M-2-因子。  相似文献   

2.
Y.Alavi,A.J.Boals,G.Chartrand,P.ErdSs和O.R.Oellermann提出下面的猜想:已知整数a1,a2,…,ak,满足n≤ai≤2n-2,1≤i≤k,且a1+a2+…+ak=rt(n+1)/2,则S=(1,2,…,n)包含有k个互不相交子集S1,S2,…,Sk,满足ai=∑(Si),1≤i≤k。推广该猜想,得到下面的定理:已知整数a1,a2,…,ak,满足ai≥n,1≤i≤k,且a1+a2+…+a4≤n(n+1)/2,则S={1,2,…,n)包含有k个互不相交子集.S1,S2,…,Sk,满足ai=∑(Si),1≤i≤k。由此定理易推出K.Ando,S.Gervacio和M.Kano证明的一个主要定理。参考文献中的一个错误同时被更正。  相似文献   

3.
设G是一个图,若删除G中任意n’个顶点的剩余子图依然是分数k-消去图,则称G为分数(k,n')-临界消去图.笔者证明了若k≥2,n,≥0,bind(G)≥^(n'+1)且6(G)≥k+n'+1,则G是分数(k,n')-临界消去图.  相似文献   

4.
设G是一个图,G的部分平方图G^*满足V(G^*)=V(G),E(G^*)=E(G)∪{uv:uv∈E(G),且J(u,v)≠φ},这里J(u,v)={w∈N(u)∩N(v),N(w)(∈)N[u]∪N[v]}.本文利用插点方法,给出了关于k,或(k+1)-连通(k≥2)图G是哈密尔顿的,1-哈密尔顿的或哈密尔顿连通的统一证明.其充分条件是在图G中关于^k∑i=1|N(Yi)|+b|N(y0)|与n(Y)的不等式,这里Y是图G的部分平方图G^*的任一独立集,对于i∈{1,2,…,k},Yi={yi,yi-1,…,yi-(b-1)}(∈ )Y(yj的下标将取模k);b是一个整数,且0<b<k+1;n(Y)=|{v∈V(G),dist(v,Y)≤2}|.  相似文献   

5.
对于一个图G,一般情况下计算它的竞赛数k(G)是很困难的。本文给出了关于完全三部图Kn1,n2,n3(n1≥n2≥n3≥2)的边团覆盖数和竞赛数:θe(Kn1,n2,n3)=n1n2 k(Kn1,n2,n3)={n1n2-n1-n2-n3+4 n1≥n2=n3 n1n2-n1-n2-n3+3 n1≥n2〉n3  相似文献   

6.
阶为n的图G的圈长分布是序列(c1,c2,…,cn),其中ci是图G中长为i的圈数.设A真包含E(Kn,n+8),在情况①G=Kn,n+8(n≥13);②G=Kn,n+8-A(|A|=1,n≥15);③G=Kn,n+8-A(|A|=2,n≥17);④G=Kn,n+8-A(|A|=3,n≥19)时,图G由其圈长分布唯一确定.  相似文献   

7.
连通图G所谓的l-边-连通度(Z—edge—connectivity),就是使图C成为至少l个分支所必须去掉的最少边数,记作λl(G),即λ1(G)=min{|E’|:E’真包含E(G),ω(G—E’)≥l}.研究了完全2-分图的l-边-连通度,得到了定理:设G=G[V1,V2]是一个完全2-分图,|V1|=r,|V2|=s,r+k=s,k≥0为整数.则图G的(k+2)-边-连通度为(k+1),即λk+2(G)=r(k+1).  相似文献   

8.
设G是一个阶为n的图,a,b,k为正整数且1≤a〈b,2≤k≤[b/a],δ(G)为G的顶点的最小度.若δ(G)≥a,n≥(a+b)(k(a+b)-2)/b,且对V(G)的任意独立子集{x1,x2,…,xk}有|NG(x1)∪NG(x2)∪…∪NG(xk)|≥an/(a+b),则G存在[a,b]-因子.  相似文献   

9.
利用插点方法,研究图的H-性,给出了k-连通图是哈密尔顿的充分条件:设G是k-连通图(k≥2),若对于每个Y∈Ik 1(G*),在G中,有σb(Y)=sum from i=o to k(|N(Yi)|>/(b k)/2(n(Y)-1) μ((b(2k-2b 1))/2-1) ,则G是哈密尔顿图.  相似文献   

10.
用|V(G)|、|E(G)|和f(G)分别表示图G的顶点数、边数和圈数.设F(k)={f(G);G是满足|E(G)|-|V(G)|=k的无环连通图},n(k)=minF(k)和N(k)=maxF(k).证明了下述结果:(1)n(k)=k+1;(2)N(k)≤2k+1;(3)对每个整数k≥1,N(k)≥2k+k(k-1)+1且当1≤k≤4时等式成立;(4)对每个整数k≥1是奇数时,N(k)≥2k3;当k≥2是偶数时,  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.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

15.
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   

16.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

17.
以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.  相似文献   

18.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

19.
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   

20.
Quality traits in wheat (Triticum aestirum L.) were studied by quantitative trait locus (QTL) analysis in a recombinant inbred line (RIL) population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross (ChSh). Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.  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