Excluding induced subgraphs II: extremal graphs
نویسندگان
چکیده
منابع مشابه
Excluding induced subgraphs: Critical graphs
Determining the cardinality and describing the structure of H-free graphs is wellinvestigated for many graphs H. In the nineties, Prömel and Steger proved that for a graph H with chromatic number k + 1 almost all graphs not containing H as a subgraph are k-colorable if and only if H contains a color-critical edge. We strengthen the concept of H-free to induced subgraph containment, proving that...
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Given two graphs, G and H, we say that H is an induced subgraph of G if V (H) ⊆ V (G), and two vertices of H are adjacent if and only if they are adjacent in G. Let F be a (possibly infinite) family of graphs. A graph G is called F -free if no member of F is isomorphic to an induced subgraph of G. A clique in a graph is a set of vertices all pairwise adjacent, and a stable set is a set of verti...
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Let K` denote the complete graph on ` vertices. We prove that there is a constant c = c(`), such that whenever p ≥ n−c, with probability tending to 1 when n goes to infinity, every maximum K`-free subgraph of the binomial random graph Gn,p is (`− 1)partite. This answers a question of Babai, Simonovits and Spencer [BSS90]. The proof is based on a tool of independent interest: we show, for instan...
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We shall prove that if L is a 3-chromatic (so called "forbidden") graph, and -R" is a random graph on n vertices, whose edges are chosen indepen-6" is a bipartite subgraph of R" of maximum size, -F" is an L-free subgraph of R" of maximum size, dently, with probability p, and then (in some sense) F" and 6" are very near to each other: almost surely they have almost the same number of edges, and ...
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ژورنال
عنوان ژورنال: Discrete Applied Mathematics
سال: 1993
ISSN: 0166-218X
DOI: 10.1016/0166-218x(93)90237-i