共查询到20条相似文献,搜索用时 281 毫秒
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本文给出了2-连通图有Hamilton圈的又一个充分条件.定理设G为有n(n>3)个顶点的2-连通图,如果对G中任意两个顶点u、v,当d(u,v)=2时,都有max(d(u),d(v))≥n/2,则G有Hamilton圈.证用反证法.假设G没有Ham... 相似文献
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设G是一个简单图,(?)e∈E(G),定义e=uv在G中的度d(e)=d(u)+d(v),其中d(u)和d(v)分别为u和v的度数。若连通图G的每个桥都有一个端点度数为1,则称G是几乎无桥的图。本文的主要结果是:设G是p≥2阶几乎无桥的简单连通图,且G≠K1,p-1若对任何无公共顶点的两边e0及e1,d(e0)+d(e1)≥p+4,则G有一个D-闭迹,从而G的线图L(G)是哈密顿的。 相似文献
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给一个图G,定义σ3(G)=min{Σ^3i=1d(vi)│{v1,v2,v3}}是G的无关集},p3(G)=min{│U^3i=1N(vi)‖{v1,v2,v3}是G中使│n^3i=1N(vi)│≠0}的无关集}。本文证明了:设G是n阶1-坚韧图,如果σ3(G)≥n,则G包含长度至少为min{n,2p3(G)+4}的圈,为个结果推广了若干已知结果,也解决了Broersma-Heuvel-Veld 相似文献
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关于可重构的局部子图 总被引:1,自引:1,他引:0
一个图G在一顶点x处的局部子图L{x}是由G的给定性质定义的包含x的子图L1,并以x为根,例如在点x处的k-局部子图是以x为根,以所有到x距离不超过k的顶点集合{u∈V(G):dG(v,x)≤k}为顶点集;以{uv∈E(G):dG(u,x)〈k,或dG(v,x)〈k}为边集的带根子图。本文证明了:对于G的局部子图L{x},如果每个L{x},x∈V(G),的顶点数(或边数)都小于G的顶点数(边数)减 相似文献
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本文解决了1982年J.A.Ross提出的两个问题,并得到如下结果:(1)设D是具有围长s>1和指数γ(D)=n+s(n-2)的n阶本原有向图,则D是Hamilton的;(2)设D是含有环的n阶本原有向图且γ(D)=2n-2,则D是Hamilton的当且仅当max{d(u,v)|γ(u,v)=2n-2}=n-2. 相似文献
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设α(G)表示简单图G=(V,E)的独立数.本文给出了α(G)的一个新的下界:α(G)≥∑v∈V(λd(v)+1)/(d(v)+λd(v)+1),其中λd(v)=max{0,βN(v)-d(v)},d(v)=|N(v)|,N(v)={w∈V|(v,w)∈E},βN(v)=minw∈N(v)d(w). 相似文献
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投影下的Gronwall不等式 总被引:7,自引:1,他引:6
本文对J.K.Hale曾提出的一类广泛的投影下的Gronwal不等式问题作了讨论,对满足u(t)≤a(t)+∫0tb(t-s)u(s)ds+∫0∞c(s)u(t+s)ds,(?)t≥0的函数u(t)∈Cb0(R+,R+)作了估计.其结果对讨论微分方程的有界解、不变流形及其Foliation和进一步讨论奇性Gronwal不等式都有意义 相似文献
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关于二部图K(m,n)-2的色唯一性 总被引:7,自引:0,他引:7
设K(m,n)-2表示从完全二部图K(m,n)中删去任意2条边所得之图.本文证明了:1.若n≥m≥3,且n+m>((n-m)2+8)1/2+1/2(n-m)2+4,则K(m,n)-2是色唯一图;2.当m≥3时,K(m,m)-2,K(m,m+1)-2和K(m,m+2)-2均是色唯一图. 相似文献
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赵雅明 《纯粹数学与应用数学》1997,13(2):99-103
在正交增量的随机积分基础上,利用Lipschitz条件,讨论了下面一类两参数随机积分方程解的唯一性。X(s,t)=Z(s,0)+Z(0,t)-Z(0,0)+∫Rstα(u,v,X)dMuv+∫Rstβ(u,v,X)dmuv+∫R^stγ1(u,v,u',v',X)dMuvdMu'v'+∫R^2stγ2(u,v,u',v',X)dMuvdmu'v'+∫R^2stγ3(u,v,u',v',X)dmuv 相似文献
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齐次生产函数条件下长期成本函数的确定方法 总被引:5,自引:0,他引:5
文章研究一般性齐次生产函数条件下长期成本函数的确定方法,证明了长期成本函数是关于产量的幂函数,并指出了长期边际成本函数和长期平均成本函数之间的特殊关系。 相似文献
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将小波引入到LMSV模型波动长记忆性的估计与检验中,提出了基于小波变换的LMSV模型波动长记忆性的伪极大似然估计法和波动长记忆性的检验方法,并对各汇率波动序列长记忆效应的大小程度进行了验证.结果表明各汇率波动序列存在长记忆效应.人民币对美元的汇率波动序列受历史信息的影响程度最高. 相似文献
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We identify the mapping class group, i.e. the space of homeomorphisms modulo isotopy, of powers of the long ray and long line as well as generalisations of the long plane obtained by taking copies of the first octant of the long plane and identifying them along their boundaries. We show that every countable group is the mapping class group of such a space. We also consider homotopy classes of continuous functions between these spaces. 相似文献
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Possible definitions of the long range dependence (LRD) of a stationary point process are discussed. Examples from the standard queueing literature are considered and shown to be amenable to yielding processes with long range count dependence. In particular the effect of the single-server queueing operator, whereby one point process is transformed into another via the mechanism of a simple queue, is examined for possible long range dependence of both the counting and interval properties of the output process. For an infinite server queue, the output is long range count dependent if and only if the input is long range count dependent. 相似文献
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In this paper, the long time behavior of the dissipative generalized (2+1)-dimensional long–short wave equations was studied in dynamics. By applying projecting operator and the eigenvalue methods, the approximate inertial manifolds were constructed. And it is proved that arbitrary trajectory of the dissipative generalized (2+1)-dimensional long–short wave equations goes into a small neighborhood of the approximate inertial manifolds after long time. 相似文献
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《Communications in Nonlinear Science & Numerical Simulation》2011,16(12):4718-4724
In this paper the lifetime of quasi-stationary states (QSS) in the α–HMF model are investigated at the long range threshold (α equals to one). It is found that QSS exist and have a diverging lifetime with system size which scales logaritmically with the number of constituents. This contrast to the exhibited power law below the long range threshold (α smaller than one) and the observed finite lifetime beyond. Also even beyond this long range threshold the long range nature of the system is displayed, namely the existence of a phase transition. As a consequence of our findings the definition of a long range system is discussed. 相似文献
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Dmitri I. Panyushev 《Advances in Mathematics》2004,186(2):307-316
We study Abelian ideals of a Borel subalgebra consisting of long roots. It is shown that methods of Cellini and Papi can be extended to this situation. A uniform expression for the number of long Abelian ideals is given. We also show that there is a one-to-one correspondence between the long Abelian ideals and B-stable commutative subalgebras in the little adjoint representation of the Langlands dual Lie algebra. 相似文献
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PAN Zhengwei CHANG Baohe SUN Lianfeng QIAN Luxi LIU Zuqin TANG Dongsheng WANG Gang XIE Sishen 《中国科学A辑(英文版)》2000,43(2):210-216
Very long and open aligned carbon nanotubes that reach about 2 mm long, an order of magnitude longer than previously reached,
have been prepared by chemical vapor deposition over silica dioxide substrates on the surface, where iron/silica nano-composite
particles are evenly positioned. The nanotubes are naturally opened at the bottom ends. The growth mechanism of the very long
and openended nanotubes is also discussed. 相似文献