For n = 1, 2, . . . , let 6, = K2+ K,,. We pose the problem of determining the Ramsey numbers r(&, B,) and demonstrate that in many cases critical colorings are available from known examples of strongly regular graphs.
A note on Ramsey numbers for books
✍ Scribed by Vladimir Nikiforov; Cecil C. Rousseau
- Publisher
- John Wiley and Sons
- Year
- 2005
- Tongue
- English
- Weight
- 87 KB
- Volume
- 49
- Category
- Article
- ISSN
- 0364-9024
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
The book with n pages B~n~ is the graph consisting of n triangles sharing an edge. The book Ramsey number r(B~m~,B~n~) is the smallest integer r such that either B~m~ ⊂ G or B~n~ ⊂ G for every graph G of order r. We prove that there exists a positive constant c such that r(B~m~,B~n~) = 2__n__ + 3 for all n ≥ cm. Our proof is based mainly on counting; we also use a result of Andrásfai, Erdős, and Sós stating that triangle‐free graphs of order n and minimum degree greater than 2__n__/5 are bipartite. © 2005 Wiley Periodicals, Inc. J Graph Theory
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It is shown that a graph of order N and average degree d that does not contain the book B m =K 1 +K 1, m as a subgraph has independence number at least Nf (d ), where f (x)t(log xÂx) (x Ä ). From this result we find that the book-complete graph Ramsey number satisfies r(B m , K n ) mn 2 Âlog(nÂe). I
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