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101.
设G是一个具有二分类(X_1,X_2)的简单偶图,|X_1|=|X_2|=n,如果对于给定的c>0,|M(S)|≥(1+c)|S|对任意满足|S|≤n/2的S(?)X_i(i=1,2)都成立,其中N(S)是S的邻集,则称G是(n,c)-扩张图.给出了(n,c)-扩张图的k-匹配数与完美匹配数之比的顺从界. 相似文献
102.
K2,4×Sn的交叉数 总被引:1,自引:0,他引:1
Garey和Johnson证明了确定图的交叉数是一个NP-完全问题.确定了笛卡尔积图$K_{2,4}\times S_{n}$的交叉数是$Z(6,n)+4n.$ 当$m\geq 5,$猜想${\rm cr}(K_{2,m}\timesS_{n})={\rm cr}(K_{2,m,n})+n\lfloor\frac{m}{2}\rfloor\lfloor\frac{m-1}{2}\rfloor$. 相似文献
103.
一个关于图是分数(k,n)-临界的邻域并条件 总被引:1,自引:0,他引:1
设G是一个图,以及k是满足1≤k的整数.一个图G在删除任意n个顶点后的子图均含有分数k-因子,则称G是一个分数(k,n)-临界图.给出了图是一个分数(k,n)-临界图的一个邻域并条件,并且该条件是最佳的. 相似文献
104.
HE Yong SHUM KarPing & WANG ZhengPan Institute of Theories on Algebra Automaton School of Computer Science Technology Hunan University of Science Technology Xiangtan China 《中国科学 数学(英文版)》2010,(5)
A semigroup S with a sub-band B is called a good B-quasi-Ehresmann semigroup if it is a Bsemiabundant semigroup satisfying the congruence condition such that B((ab)+)abB((ab)*)aB(a*)B(b+)b for all a,b ∈S.We show that every good B-quasi-Ehresmann semigroup has a global representation and a standard representation.As a special case,the structure of good quasi-adequate semigroups is described. 相似文献
105.
In this paper, we introduce Green's .-relations on semirings and define [left, right] adequate semirings to explore additively non-regular semirings. We characterize the semirings which are strong b-lattices of [left, right] skew-halfrings. Also, as further generalization, the semirings are described which are subdirect products of an additively commutative idempotent semiring and a [left, right] skew-halfring. We extend results of constructions of generalized Clifford semirings (given by M. K. Sen, S. K. MaRy, K. P. Shum, 2005) and the semirings which are subdirect products of a distributive lattice and a ring (given by S. Ghosh, 1999) to additively non-regular semirings. 相似文献
106.
Wei Wang 《Geometriae Dedicata》2013,164(1):273-285
In this article, some Brunn–Minkowski type inequalities for (radial) Blaschke–Minkowski homomorphisms with respect to (radial) L p Minkowski addition are established. 相似文献
107.
108.
Jiming Yang Yanping Chen Zhiguang Xiong 《Numerical Methods for Partial Differential Equations》2013,29(6):1801-1820
An efficient time‐stepping procedure is investigated for a two‐dimensional compressible miscible displacement problem in porous media in which the mixed finite element method with Raviart‐Thomas space is applied to the flow equation, and the transport one is solved by the symmetric interior penalty discontinuous Galerkin approximation on Cartesian meshes. Based on the projection interpolations and the induction hypotheses, a superconvergence error estimate is obtained. During the analysis, an extension of the Darcy velocity along the Gauss line is also used in the evaluation of the coefficients in the Galerkin procedure for the concentration. © 2013 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2013 相似文献
109.
《Applied Mathematics Letters》2002,15(5):533-540
In this paper, we derive explicit formulas for computing the roots of a quaternionic quadratic polynomial. 相似文献
110.
A direct synthesis of 3-(bromomethylene)isobenzofuran-1(3H)-ones from 2-alkynylbenzoic acids is developed through a regioselective 5-exo-dig bromocyclization. The reaction proceeds smoothly with a broad substrate scope. The products can be further elaborated via a palladium-catalyze cross-coupling reaction, or can convert to other heterocycles through simple operation. Preliminary mechanistic studies reveal that this transformation undergoes a radical process. 相似文献