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181.
We consider L1-solutions of the following refinement type equations
182.
Warwick de Launey 《Journal of Combinatorial Theory, Series A》2009,116(4):1002-1008
It is conjectured that Hadamard matrices exist for all orders 4t (t>0). However, despite a sustained effort over more than five decades, the strongest overall existence results are asymptotic results of the form: for all odd natural numbers k, there is a Hadamard matrix of order k2[a+blog2k], where a and b are fixed non-negative constants. To prove the Hadamard Conjecture, it is sufficient to show that we may take a=2 and b=0. Since Seberry's ground-breaking result, which showed that we may take a=0 and b=2, there have been several improvements where b has been by stages reduced to 3/8. In this paper, we show that for all ?>0, the set of odd numbers k for which there is a Hadamard matrix of order k22+[?log2k] has positive density in the set of natural numbers. The proof adapts a number-theoretic argument of Erdos and Odlyzko to show that there are enough Paley Hadamard matrices to give the result. 相似文献
183.
Zeev Nutov 《Discrete Applied Mathematics》2009,157(1):112-117
Let G=(V,E) be a directed/undirected graph, let s,t∈V, and let F be an intersecting family on V (that is, X∩Y,X∪Y∈F for any intersecting X,Y∈F) so that s∈X and t∉X for every X∈F. An edge set I⊆E is an edge-cover of F if for every X∈F there is an edge in I from X to V−X. We show that minimal edge-covers of F can be listed with polynomial delay, provided that, for any I⊆E the minimal member of the residual family FI of the sets in F not covered by I can be computed in polynomial time. As an application, we show that minimal undirected Steiner networks, and minimal k-connected and k-outconnected spanning subgraphs of a given directed/undirected graph, can be listed in incremental polynomial time. 相似文献
184.
本文讨论的是集值优化问题Benson真有效解的高阶Fritz John型最优性条件,利用Aubin和Fraukowska引入的高阶切集和凸集分离定理,在锥-似凸映射的假设条件下,获得了带广义不等式约束的集值优化问题Benson真有效解的高阶Fritz John型必要和充分性条件. 相似文献
185.
Difference systems of sets (DSS) are combinatorial configurations that arise in connection with code synchronization. This paper proposes a new method to construct DSSs, which uses known DSSs to partition some of the cosets of Zv relative to subgroup of order k, where v = km is a composite number. As applications, we obtain some new optimal DSSs. 相似文献
186.
AbstractThe allocation problem of rewards or costs is a central question for individuals and organizations contemplating cooperation under uncertainty. The involvement of uncertainty in cooperative games is motivated by the real world where noise in observation and experimental design, incomplete information and further vagueness in preference structures and decision-making play an important role. The theory of cooperative ellipsoidal games provides a new game theoretical angle and suitable tools for answering this question. In this paper, some solution concepts using ellipsoids, namely the ellipsoidal imputation set, the ellipsoidal dominance core and the ellipsoidal stable sets for cooperative ellipsoidal games, are introduced and studied. The main results contained in the paper are the relations between the ellipsoidal core, the ellipsoidal dominance core and the ellipsoidal stable sets of such a game. 相似文献
187.
Bau-Sen Du 《Journal of Difference Equations and Applications》2013,19(11):1843-1851
188.
为了得到理想的技术创新选择方案,论文从技术创新的实际出发,从实力、潜力和外部环境三个角度选择了一组反映技术创新项目实际情况的评价指标。并借助Vague集理论,通过TOPSIS中正负理想解的思想定义了任意创新方案的评价指标值,运用Vague集理论中距离的概念构建了新的评价方法,进而得到了满意的评价结果。该方法一方面体现了Vague集理论描述不确定性问题的优点,另一方面借助TOPSIS思想满足了方案评价的基本准则。这一思想和方法的提出不仅为Vague集理论研究提供了新的应用领域,也为技术创新的研究提供了新的思路和方法。 相似文献
189.
LI Qiuyue & REN Yanxia LMAM School of Mathematical Sciences Peking University Beijing China 《中国科学A辑(英文版)》2005,48(12):1683-1695
This paper gives probabilistic expressions of the minimal and maximal positive solutions of the partial differential equation -1/2△v(x) γ(x)v(x)α = 0 in D, where D is a regular domain in Rd(d ≥ 3) such that its complement Dc is compact, γ(x) is a positive bounded integrable function in D, and 1 < α≤ 2. As an application, some necessary and sufficient conditions for a compact set to be S-polar are presented. 相似文献
190.
本文在自共轭的条件下,找到了群G2×Gp(p为奇素数)中相对于2阶子群的(2a-1pb,2a c-1/2 pb/2,2c)-BS的一种下降构造法和一种嵌套构造法,同时给出了Gp的一个指数界,特别地当G2(?) Z2a×Z2a2时,有a2=a1且c=1或2,或者a2=a1-1且c=1. 相似文献