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81.
令Sk 1表示k 1阶星图,φ^*(2k,n)表示2Sk 1的两个k度点分别与路Pn的两个1度点重迭后得到的图.对于1≤i≤2k n=1,用Srq 2^*(i)表示rφ^*(2k,n)的每个分支的第i个顶点依次与Sr 1的r个1度点重迭后得到的新图;Гpq 1^*(i)表示pφ^*(2k,n)的每个分支的第i个顶点及其对称点依次与S2p 1的2p个1度点配对且重迭后得到的新图.我们通过研究这两类新图与一定数目的孤立点组成的并图的伴随多项式的因式分解,证明了上述并图的补图的色等价图的结构定理. 相似文献
82.
In this paper the methods of wave theory based prestack depth migration and their implementation are studied. Using the splitting of wave operator, the wavefield extrapolation equations are deduced and the numerical schemes are presented. The numerical tests for SEG/EAEG model with MPI are performed on the PC-cluster. The numerical re- 相似文献
83.
Let K
m,nbe a complete bipartite graph with two partite sets having m and n vertices, respectively. A K
p,q-factorization of K
m,n is a set of edge-disjoint K
p,q-factors of K
m,n which partition the set of edges of K
m,n. When p = 1 and q is a prime number, Wang, in his paper “On K
1,k
-factorizations of a complete bipartite graph” (Discrete Math, 1994, 126: 359—364), investigated the K
1,q
-factorization of K
m,nand gave a sufficient condition for such a factorization to exist. In the paper “K
1,k
-factorizations of complete bipartite graphs” (Discrete Math, 2002, 259: 301—306), Du and Wang extended Wang’s result to the
case that q is any positive integer. In this paper, we give a sufficient condition for K
m,n to have a K
p,q-factorization. As a special case, it is shown that the Martin’s BAC conjecture is true when p : q = k : (k+ 1) for any positive integer k. 相似文献
84.
A. V. Balakrishnan 《Applied Mathematics and Optimization》1995,31(2):177-187
In this paper we generalize the Kalman-Yakubovic lemma to infinite dimensions—or, more precisely, to semigroups of operators over a Hilbert space. The proof differs substantially from the finite-dimensional version and is based on the Paley-Wiener-Helson-Lowdenslager factorization theorem. 相似文献
85.
大型对称不定箭形线性方程组的分解方法 总被引:4,自引:1,他引:3
1 引言 首先考虑2×2矩阵 显然当k>1/2时,矩阵K是对称正定的,且K可以分解成Cholesky因子:当k=1/2时,K为奇异矩阵;而当k<1/2时,K为对称不定矩阵,这时K有广义Cholesky分解式:并且这种分解是稳定的,一般地我们给出定义 定义1.1 设有矩阵K∈R~((m+n)×(m+n)),若总存在排列矩阵P∈R~((m+n)×(m+n))和对称正定矩阵H∈R~(m×n)、G∈R(m×m)使得则称矩阵K为对称拟定(Symmetric quasidefinite)矩阵。 相似文献
86.
Lilia Yu. Kolotilina 《Numerical Algorithms》2006,42(3-4):247-280
Using a unified approach based on the monotonicity property of the Perron root and its circuit extension, a series of exact two-sided bounds for the Perron root of a nonnegative matrix in terms of paths in the associated directed graph is obtained. A method for deriving the so-called mixed upper bounds is suggested. Based on the upper bounds for the Perron root, new diagonal dominance type conditions for matrices are introduced. The singularity/nonsingularity problem for matrices satisfying such conditions is analyzed, and the associated eigenvalue inclusion sets are presented. In particular, a bridge connecting Gerschgorin disks with Brualdi eigenvalue inclusion sets is found. Extensions to matrices partitioned into blocks are proposed. 相似文献
87.
We establish, for various scenarios, whether or not interruptible exact stationary sampling is possible when a finite-state Markov chain can only be viewed passively. In particular, we prove that such sampling is not possible using a single copy of the chain. Such sampling is possible when enough copies of the chain are available, and we provide an algorithm that terminates with probability one. 相似文献
88.
89.
《Journal of Pure and Applied Algebra》2023,227(2):107191
In a previous work, we have introduced a weakening of Quillen model categories called weak model categories. They still allow all the usual constructions of model category theory, but are easier to construct and are in some sense better behaved. In this paper we continue to develop their general theory by introducing combinatorial and accessible weak model categories. We give simple necessary and sufficient conditions under which such a weak model category can be extended into a left and/or right semi-model category. As an application, we recover Cisinski-Olschok theory and generalize it to weak and semi-model categories. We also provide general existence theorems for both left and right Bousfield localization of combinatorial and accessible weak model structures, which combined with the results above gives existence results for left and right Bousfield localization of combinatorial and accessible left and right semi-model categories, generalizing previous results of Barwick. Surprisingly, we show that any left or right Bousfield localization of an accessible or combinatorial Quillen model category always exists, without properness assumptions, and is simultaneously both a left and a right semi-model category, without necessarily being a Quillen model category itself. 相似文献
90.
从传统的混凝土分离裂缝模型和弥散裂缝模型出发,使用不同的模型模拟不同发展阶段的混凝土裂缝,并利用无网格方法可以灵活布置节点和边界的优点,使分离裂缝模型的使用得到很大的简化。通过在宏观裂缝表面布置基于试验结果的混凝土与混凝土界面单元,正确地模拟了裂缝表面抗剪能力的变化。算例表明,使用本文方法可以准确模拟斜拉破坏混凝土梁的破坏过程,且精度和数值稳定性要高于传统的有限元弥散裂缝方法。 相似文献