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151.
元如林 《南昌大学学报(理科版)》1992,16(3):1
本文主要讨论格序群扭类的复盖,特别是极小扭类(即零扭类的复盖)。通过引入强齐次l-群和强J-单的l-群的概念,得到了一个扭类是极小扭类的几个充分必要条件,以及关于扭类复盖的几个结果。并由此给出了N中的相对于N的极扭类与N的极小扭类之间的关系,证明了N中的相对于N的极扭类全 相似文献
152.
Yoshimi Egawa Ralph J. Faudree Ervin Györi Yoshiyasu Ishigami Richard H. Schelp Hong Wang 《Graphs and Combinatorics》2000,16(1):81-92
Dirac and Ore-type degree conditions are given for a graph to contain vertex disjoint cycles each of which contains a previously
specified edge. One set of conditions is given that imply vertex disjoint cycles of length at most 4, and another set of conditions
are given that imply the existence of cycles that span all of the vertices of the graph (i.e. a 2-factor). The conditions
are shown to be sharp and give positive answers to conjectures of Enomoto in [3] and Wang in [5].
Revised: July 28, 1999 相似文献
153.
度量空间的紧覆盖s映射 总被引:8,自引:0,他引:8
本文引入了紧有限分解网的概念,给出度量空间的紧覆盖s象的内在刻画并由此导出度量空间s映射的系列结论,部分地回答了Michael-Nagami问题. 相似文献
154.
令G为一具有n个节点的平面近三角剖分图,C为G的一个少圈二重覆盖(SCDC).本文首先给出了G的一些生成元,由此可以得到G的一个SCDC.若G为一外平面近三角剖分图,得到 |C|≤n-2的一充分必要条件;若 G至少有一个内点,得到|C|≤n-2的一充分条件. 相似文献
155.
In this short note we obtain the full set of inequalities that define the convex hull of a 0–1 knapsack constraint presented
in Weismantel (1997). For that purpose we use our O(n) procedures for identifying maximal cliques and non-dominated extensions
of consecutive minimal covers and alternates, as well as our schemes for coefficient increase based tightening cover induced
inequalities and coefficient reduction based tightening general 0–1 knapsack constraints. 相似文献
156.
Edgar E. Enochs Overtoun M. G. Jenda Jinzhong Xu 《Algebras and Representation Theory》1999,2(3):259-268
Before his death, Auslander announced that every finitely generated module over a local Gorenstein ring has a minimal Cohen–Macaulay approximation. Yoshimo extended Auslander's result to local Cohen–Macaulay rings admitting a dualizing module.Over a local Gorenstein ring the finitely generated maximal Cohen–Macaulay modules are the finitely generated Gorenstein projective modules so in fact Auslander's theorem says finitely generated modules over such rings have Gorenstein projective covers. We extend Auslander's theorem by proving that over a local Cohen–Macaulay ring admitting a dualizing module all finitely generated modules of finite G-dimension (in Auslander's sense) have a Gorenstein projective cover. Since all finitely generated modules over a Gorenstein ring have finite G-dimension, we recover Auslander's theorem when R is Gorenstein. 相似文献
157.
Romeo Rizzi 《Journal of Graph Theory》2000,33(3):138-139
We give a short proof of the following basic fact in matching theory: in a bipartite graph the maximum size of a matching equals the minimum size of a node cover. © John Wiley & Sons, Inc. J Graph Theory 33: 138–139, 2000 相似文献
158.
In previous papers, the authors computed the Poincaré series of some (multi-index) filtrations on the ring of germs of functions on a rational surface singularity. These Poincaré series were expressed as the integer parts of certain fractional power series, whose interpretation was not given. In this paper, we show that, up to a simple change of variables, these fractional power series are reductions of the equivariant Poincaré series for filtrations on the ring of germs of functions on the universal Abelian cover of the surface. We compute these equivariant Poincaré series. 相似文献
159.
Ladislav Bican 《Czechoslovak Mathematical Journal》2008,58(2):561-568
In the class of all exact torsion theories the torsionfree classes are cover (pre-cover) classes if and only if the classes
of torsionfree relatively injective modules or relatively exact modules are cover (precover) classes, and this happens exactly
if and only if the torsion theory is of finite type. Using the transfinite induction in the second half of the paper a new
construction of a torsionfree relatively injective cover of an arbitrary module with respect to Goldie’s torsion theory of
finite type is presented.
This research has been partially supported by the Grant Agency of the Czech Republic, grant #GAČR 201/06/0510 and also by
the institutional grant MSM 0021620839. 相似文献
160.
本文给出基本群为剩余有限的紧致3维流形何时有有限多有限复迭,何时有有限多有限循环复迭的充要条件。 相似文献