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1.
We deal with MAXH0-FREE PARTIAL SUBGRAPH. We mainly prove that 3-locally optimum solutions achieve approximation ratio (δ0+1)/(B+2+ν0), where B=maxv∈VdG(v), δ0=minv∈V(H0)dH0(v) and ν0=(|V(H0)|+1)/δ0. Next, we show that this ratio rises up to 3/(B+1) when H0=K3. Finally, we provide hardness results for MAXK3-FREE PARTIAL SUBGRAPH. 相似文献
2.
An m‐covering of a graph G is a spanning subgraph of G with maximum degree at most m. In this paper, we shall show that every 3‐connected graph on a surface with Euler genus k ≥ 2 with sufficiently large representativity has a 2‐connected 7‐covering with at most 6k ? 12 vertices of degree 7. We also construct, for every surface F2 with Euler genus k ≥ 2, a 3‐connected graph G on F2 with arbitrarily large representativity each of whose 2‐connected 7‐coverings contains at least 6k ? 12 vertices of degree 7. © 2003 Wiley Periodicals, Inc. J Graph Theory 43: 26–36, 2003 相似文献
3.
设G是2-连通图,c(G)是图G的最长诱导圈的长度,c′(G)是图G的最长诱导2-正则子图的长度。本文我们用图的特征值给出了c(G)和c′(G)的几个上界。 相似文献
4.
5.
Shy-Der Lin 《Journal of Mathematical Analysis and Applications》2004,294(2):399-411
The main object of this paper is to investigate several general families of hypergeometric polynomials and their associated single-, double-, and triple-integral representations. Some known or new consequences of the general results presented here, involving such classical orthogonal polynomials as the Jacobi, Laguerre, Hermite, and Bessel polynomials, and various other relatively less familiar hypergeometric polynomials, are also considered. Each of the integral representations, which are derived in this paper, may be viewed also as a linearization relationship for the product of two different members of the associated family of hypergeometric polynomials. 相似文献
6.
关于k—消去图的若干新结果 总被引:2,自引:0,他引:2
汪长平 《数学物理学报(A辑)》1998,18(3):302-309
设G是一个图.k是自然数.图G的一个k-正则支撑子图称为G的一个k-因子.若对于G的每条边e.G—e都存在一个k-因子,则称G是一个k-消去图.该文得到了一个图是k-消去图的若干充分条件,推广了文[2—4]中有关结论. 相似文献
7.
The goal of this paper is to compute the shape Hessian for a generalized Oseen problem with nonhomogeneous Dirichlet boundary
condition by the velocity method. The incompressibility will be treated by penalty approach. The structure of the shape gradient
and shape Hessian with respect to the shape of the variable domain for a given cost functional are established by an application
of the Lagrangian method with function space embedding technique.
This work was supported by the National Natural Science Fund of China (No. 10371096) for ZM Gao and YC Ma. 相似文献
8.
《Discrete Mathematics》2022,345(3):112739
A ballot permutation is a permutation π such that in any prefix of π the descent number is not more than the ascent number. By using a reversal-concatenation map, we (i) give a formula for the joint distribution (pk, des) of the peak and descent statistics over ballot permutations, (ii) connect this distribution and the joint distribution (pk, des) over ordinary permutations in terms of generating functions, and (iii) confirm Spiro's conjecture which finds the equidistribution of the descent statistic for ballot permutations and an analogue of the descent statistic for odd order permutations. 相似文献
9.
L. I. Makarov 《Journal of Structural Chemistry》2005,46(4):738-743
Some questions emerged from electronic data processing of molecular structures (graphs) and its fragments have been considered in this work. Quantitative estimations of subgraph positions in molecular graphs are presented and some properties of their maximal common subgraphs are described. 相似文献
10.
A finite point method for solving compressible flow problems involving moving boundaries and adaptivity is presented. The numerical methodology is based on an upwind‐biased discretization of the Euler equations, written in arbitrary Lagrangian–Eulerian form and integrated in time by means of a dual‐time steeping technique. In order to exploit the meshless potential of the method, a domain deformation approach based on the spring network analogy is implemented, and h‐adaptivity is also employed in the computations. Typical movable boundary problems in transonic flow regime are solved to assess the performance of the proposed technique. In addition, an application to a fluid–structure interaction problem involving static aeroelasticity illustrates the capability of the method to deal with practical engineering analyses. The computational cost and multi‐core performance of the proposed technique is also discussed through the examples provided. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献