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1.
模糊关系矩阵传递闭包的Warshall算法 总被引:8,自引:2,他引:6
通过对照关系的传递闭包和模糊关系的传递闭包,把求关系矩阵的传递闭包的算法完整地推广到模糊关系矩阵上。 相似文献
2.
J. Ježek 《Czechoslovak Mathematical Journal》2004,54(1):233-246
We investigate congruences in one-element extensions of algebras in the variety generated by tournaments. 相似文献
4.
We prove that if T is a tournament of order n > 6 in which any 4-sub-tournament is hamiltonian or transitive, then T is reconstructible in the sense of Ulam. 相似文献
5.
Brenda J. Latka 《Journal of Graph Theory》2003,42(3):165-192
A finite tournament T is tight if the class of finite tournaments omitting T is well‐quasi‐ordered. We show here that a certain tournament N5 on five vertices is tight. This is one of the main steps in an exact classification of the tight tournaments, as explained in [10]; the third and final step is carried out in [11]. The proof involves an encoding of the indecomposable tournaments omitting N5 by a finite alphabet, followed by an application of Kruskal's Tree Theorem. This problem arises in model theory and in computational complexity in a more general form, which remains open: the problem is to give an effective criterion for a finite set {T1,…,Tk} of finite tournaments to be tight in the sense that the class of all finite tournaments omitting each of T1,…,Tk is well‐quasi‐ordered. © 2003 Wiley Periodicals, Inc. J Graph Theory 42: 165–192, 2003 相似文献
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Bousquet, Lochet and Thomassé recently gave an elegant proof that for any integer , there is a least integer such that any tournament whose arcs are coloured with colours contains a subset of vertices of size with the property that any vertex not in admits a monochromatic path to some vertex of . In this note we provide a lower bound on the value . 相似文献
9.
Mehdi?AlaeiyanEmail author Shaban?Sedghi 《Southeast Asian Bulletin of Mathematics》2003,26(2):181-184
Let G be a intransitive permutation group on a set with no fixed point in ; let m, n be a positive integer and let |g – | m, for every
and g G. When G has t orbits and degree n close to [2mp/(p – 1)] + t – 1, this paper constructs such a group with m close to [n(p – 1)/2p].AMS Subject Classification: 20BXX. 相似文献
10.
A family of subspaces of a complex separable Hilbert space is transitive if every bounded operator which leaves each of its
members invariant is scalar. This article surveys some results concerning transitive families of small cardinality, and adds
some new ones. The minimum cardinality of a transitive family in finite dimensions (greater than 2) is 4. In infinite dimensions
a transitive pair of linear manifolds exists but the minimum cardinality of a transitive family of dense operator ranges or
norm-closed subspaces is not known. However, a transitive family of dense operator ranges with 5 elements can be found, and
so can a transitive family of norm-closed subspaces with 4 elements. In finite dimensions (> 1) three nest algebras (corresponding
to maximal nests) can intersect in the scalar operators, but two cannot. It is not known if this is the case in infinite dimensions
for maximal nests of type ω + 1. Four such nest algebras can intersect in the scalar operators.
Received June 15, 2002, Accepted November 27, 2002 相似文献