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11.
It is shown that the Cartesian product of two nontrivial connected graphs admits a nowhere‐zero 4‐flow. If both factors are bipartite, then the product admits a nowhere‐zero 3‐flow. © 2003 Wiley Periodicals, Inc. J Graph Theory 43: 93–98, 2003 相似文献
12.
For each infinite cardinal κ, we give examples of 2κ many non‐isomorphic vertex‐transitive graphs of order κ that are pairwise isomorphic to induced subgraphs of each other. We consider examples of graphs with these properties that are also universal, in the sense that they embed all graphs with smaller orders as induced subgraphs. © 2003 Wiley Periodicals, Inc. J Graph Theory 43: 99–106, 2003 相似文献
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15.
Robert W. Baddeley Cheryl E. Praeger Csaba Schneider 《Transactions of the American Mathematical Society》2006,358(4):1619-1641
A permutation group is innately transitive if it has a transitive minimal normal subgroup, which is referred to as a plinth. We study the class of finite, innately transitive permutation groups that can be embedded into wreath products in product action. This investigation is carried out by observing that such a wreath product preserves a natural Cartesian decomposition of the underlying set. Previously we classified the possible embeddings in the case where the plinth is simple. Here we extend that classification and identify several different types of Cartesian decompositions that can be preserved by an innately transitive group with a non-abelian plinth. These different types of decompositions lead to different types of embeddings of the acting group into wreath products in product action. We also obtain a full characterisation of embeddings of innately transitive groups with diagonal type into such wreath products.
16.
Discrete-time GI/Geo/1 queue with multiple working vacations 总被引:2,自引:0,他引:2
Consider the discrete time GI/Geo/1 queue with working vacations under EAS and LAS schemes. The server takes the original
work at the lower rate rather than completely stopping during the vacation period. Using the matrix-geometric solution method,
we obtain the steady-state distribution of the number of customers in the system and present the stochastic decomposition
property of the queue length. Furthermore, we find and verify the closed property of conditional probability for negative
binomial distributions. Using such property, we obtain the specific expression for the steady-state distribution of the waiting
time and explain its two conditional stochastic decomposition structures. Finally, two special models are presented.
相似文献
17.
证明如下结果,设X是Banach空间,则X是无限维的充分必要的条件是存在不含内点的非空凸集B,使得B不在任何一个闭超平面上。 相似文献
18.
Let G be a simple graph with adjacency matrix A(G) and (G,x) the permanental polynomial of G. Let G × H denotes the Cartesian product of graphs G and H. Inspired by Kleins idea to compute the permanent of some matrices (Mol. Phy. 31 (3) (1976) 811–823), in this paper in terms of some orientation of graphs we study the permanental polynomial of a type of graphs. Here are some of our main results.1.If G is a bipartite graph containing no subgraph which is an even subdivision of K
2,3, then G has an orientation G
e such that (G,x) = det (xI-A(G
e
)), where A(G
e
) denotes the skew adjacency matrix of G
e.2.Let G be a 2-connected outerplanar bipartite graph with n vertices. Then there exists a 2-connected outerplanar bipartite graph
with 2n+2 vertices such that (G,x) is a factor of
.3.Let T be an arbitrary tree with n vertices. Then
, where
1
,
2
, ...,
n are the eigenvalues of T. 相似文献
19.
A second order accurate method in the infinity norm is proposed for general three dimensional anisotropic elliptic interface problems in which the solution and its derivatives, the coefficients, and source terms all can have finite jumps across one or several arbitrary smooth interfaces. The method is based on the 2D finite element-finite difference (FE-FD) method but with substantial differences in method derivation, implementation, and convergence analysis. One of challenges is to derive 3D interface relations since there is no invariance anymore under coordinate system transforms for the partial differential equations and the jump conditions. A finite element discretization whose coefficient matrix is a symmetric semi-positive definite is used away from the interface; and the maximum preserving finite difference discretization whose coefficient matrix part is an M-matrix is constructed at irregular elements where the interface cuts through. We aim to get a sharp interface method that can have second order accuracy in the point-wise norm. We show the convergence analysis by splitting errors into several parts. Nontrivial numerical examples are presented to confirm the convergence analysis. 相似文献
20.
A Cartesian decomposition of a coherent configuration is defined as a special set of its parabolics that form a Cartesian decomposition of the underlying set. It turns out that every tensor decomposition of comes from a certain Cartesian decomposition. It is proved that if the coherent configuration is thick, then there is a unique maximal Cartesian decomposition of ; i.e., there is exactly one internal tensor decomposition of into indecomposable components. In particular, this implies an analog of the Krull–Schmidt theorem for the thick coherent configurations. A polynomial-time algorithm for finding the maximal Cartesian decomposition of a thick coherent configuration is constructed. 相似文献