V. Chva tal conjectured in 1985 that a minimal imperfect graph G cannot have a skew cutset (i.e., a cutset S decomposable into disjoint sets A and B joined by all possible edges). We prove here the conjecture in the particular case where at least one of A and B is a stable set. 2001 Elsevier Science
Complete Multi-partite Cutsets in Minimal Imperfect Graphs
β Scribed by G. Cornuejols; B. Reed
- Publisher
- Elsevier Science
- Year
- 1993
- Tongue
- English
- Weight
- 316 KB
- Volume
- 59
- Category
- Article
- ISSN
- 0095-8956
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β¦ Synopsis
We show that a minimal imperfect graph (G) cannot contain a cutset (C) which induces a complete multi-partite graph unless (C) is a stable set and (G) is an odd hole. This generalizes a result of Tucker, who proved that the only minimal imperfect graphs containing stable cutsets are the odd holes. It is also a special case of a conjecture of ChvΓ‘tal. 1993 Academic Press, Inc.
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## Abstract We calculate the asymptotic value of the choice number of complete multiβpartite graphs, given certain limitations on the relation between the sizes of the different sides. In the bipartite case, we prove that if __n__~0~ β€ __n__~1~ and log__n__~0~ β« loglog__n__~1~, then $ch(K\_{n\_{0},