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991.
利用重合度理论中的延拓定理研究非自治周期食饵—捕食系统的非平凡周期解存在性,给出了周期解存在的充分条件. 相似文献
992.
万树平 《应用数学与计算数学学报》2010,24(1):45-52
针对方案属性值为Vague值的多属性群决策问题,提出了一种新的专家权重的确定方法.定义了Vague值的得分函数、贴近度、运算法则以及信息集成算子.根据专家评判的相似度矩阵,通过其最大模特征值所对应的特征向量客观地确定了专家的权重,进而提出了新的群决策方法.制造资源应用实例验证了方法的可行性和合理性. 相似文献
993.
An L(h,k)-labeling of a graph G is an integer labeling of vertices of G, such that adjacent vertices have labels which differ by at least h, and vertices at distance two have labels which differ by at least k. The span of an L(h,k)-labeling is the difference between the largest and the smallest label. We investigate L(h,k)-labelings of trees of maximum degree Δ, seeking those with small span. Given Δ, h and k, span λ is optimal for the class of trees of maximum degree Δ, if λ is the smallest integer such that every tree of maximum degree Δ has an L(h,k)-labeling with span at most λ. For all parameters Δ,h,k, such that h<k, we construct L(h,k)-labelings with optimal span. We also establish optimal span of L(h,k)-labelings for stars of arbitrary degree and all values of h and k. 相似文献
994.
Let G=(V,E) be a simple, undirected graph of order n and size m with vertex set V, edge set E, adjacency matrix A and vertex degrees Δ=d1≥d2≥?≥dn=δ. The average degree of the neighbor of vertex vi is . Let D be the diagonal matrix of degrees of G. Then L(G)=D(G)−A(G) is the Laplacian matrix of G and Q(G)=D(G)+A(G) the signless Laplacian matrix of G. Let μ1(G) denote the index of L(G) and q1(G) the index of Q(G). We survey upper bounds on μ1(G) and q1(G) given in terms of the di and mi, as well as the numbers of common neighbors of pairs of vertices. It is well known that μ1(G)≤q1(G). We show that many but not all upper bounds on μ1(G) are still valid for q1(G). 相似文献
995.
Min Chen 《Discrete Mathematics》2010,310(20):2705-2713
Let G be a graph and let c: be an assignment of 2-elements subsets of the set {1,…,5} to the vertices of G such that for any two adjacent vertices u and v,c(u) and c(v) are disjoint. Call such a coloring c a (5, 2)-coloring of G. A graph is (5,2)-colorable if and only if it has a homomorphism to the Petersen graph.The maximum average degree of G is defined as . In this paper, we prove that every triangle-free graph with is homomorphic to the Petersen graph. In other words, such a graph is (5, 2)-colorable. Moreover, we show that the bound on the maximum average degree in our result is best possible. 相似文献
996.
Pandian M. Vasant 《Fuzzy Optimization and Decision Making》2003,2(3):229-241
In this paper, a new fuzzy linear programming based methodology using a specific membership function, named as modified logistic membership function is proposed. The modified logistic membership function is first formulated and its flexibility in taking up vagueness in parameters is established by an analytical approach. This membership function is tested for its useful performance through an illustrative example by employing fuzzy linear programming. The developed methodology of FLP has provided a confidence in applying to real life industrial production planning problem. This approach of solving industrial production planning problem can have feed back within the decision maker, the implementer and the analyst. In such case this approach can be called as IFLP (Interactive Fuzzy Linear Programming). There is a possibility to design the self organizing of fuzzy system for the mix products selection problem in order to find the satisfactory solution. The decision maker, the analyst and the implementer can incorporate their knowledge and experience to obtain the best outcome. 相似文献
997.
Hans-Joachim Baues 《Compositio Mathematica》1998,110(1):50-64
For manifolds M,M of the form S2 e4 e6 we compute the homomorphisms H*M H*M between homology groups which are realizable by a map F: M M. 相似文献
998.
We consider the structure of Kr‐free graphs with large minimum degree, and show that such graphs with minimum degree δ>(2r ? 5)n/(2r ? 3) are homomorphic to the join Kr ? 3∨H, where H is a triangle‐free graph. In particular this allows us to generalize results from triangle‐free graphs and show that Kr‐free graphs with such a minimum degree have chromatic number at most r +1. We also consider the minimum‐degree thresholds for related properties. Copyright © 2010 John Wiley & Sons, Ltd. 66:319‐331, 2011 相似文献
999.
Using the cone theory and lattice structure, we discuss the existence of asymptotic bifurcation points and the global bifurcation of nonlinear operators which are not assumed to be cone mappings and may not be Frechet differentiable at points at infinity. As an application, the structure of the set of solutions of the superlinear Sturm-Liouville problems is investigated. 相似文献
1000.