منابع مشابه
On a Two-Sided Turan Problem
Given positive integers n, k, t, with 2 ≤ k ≤ n, and t < 2, let m(n, k, t) be the minimum size of a family F of nonempty subsets of [n] such that every k-set in [n] contains at least t sets from F , and every (k − 1)-set in [n] contains at most t− 1 sets from F . Sloan et. al [11] determined m(n, 3, 2) and Füredi et. al [6] studied m(n, 4, t) for t = 2, 3. We consider m(n, 3, t) and m(n, 4, t) ...
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For every countable, connected graph A containing no one-way infinite path the following is shown: Let G be an arbitrary graph which contains for every positive integer n a system of n disjoint graphs each isomorphic to a subdivision of A. Then G also contains infinitely many disjoint subgraphs each isomorphic to a subdivision of A. In addition, corrections of errors are given that occur unfort...
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(To the memory of S. Minakshisundaram) 1. In the second paper of this series we proved the following two theorems. Let Sn stand for the symmetric group with n letters, P a generic element of it and O(P) its order. Then we have THEOREM A. For almost all P's in Sn , i .e. with the exception of o(n!) P's at most, 0(P) is divisible by all prime powers not exceeding log n 1 + 3 log log log n w(n) lo...
متن کاملChromaticity of Turan Graphs with At Most Three Edges Deleted
Let $P(G,lambda)$ be the chromatic polynomial of a graph $G$. A graph $G$ ischromatically unique if for any graph $H$, $P(H, lambda) = P(G,lambda)$ implies $H$ is isomorphic to $G$. In this paper, we determine the chromaticity of all Tur'{a}n graphs with at most three edges deleted. As a by product, we found many families of chromatically unique graphs and chromatic equivalence classes of graph...
متن کاملOn a Conjecture concerning Vertex-transitive Graphs
In this article we define a minor relation, which is stronger than the classical one, but too strong to become a well-quasi-order on the class of finite graphs. Nevertheless, with this terminology we are able to introduce a conjecture, which would imply the Lovasz conjecture and give an interesting insight on the symmetry of vertex-transitive graphs, if true. Though it could become an approach ...
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ژورنال
عنوان ژورنال: Fundamenta Mathematicae
سال: 1955
ISSN: 0016-2736,1730-6329
DOI: 10.4064/fm-41-1-137-145