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arXiv · 0803.1860

Two remarks on the Burr-Erdos conjecture

Jacob Fox·Benny Sudakov
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Abstract

The Ramsey number r(H) of a graph H is the minimum positive integer N such that every two-coloring of the edges of the complete graph K_N on N vertices contains a monochromatic copy of H. A graph H is d-degenerate if every subgraph of H has minimum degree at most d. Burr and Erdős in 1975 conjectured that for each positive integer d there is a constant c_d such that r(H) \leq c_dn for every d-degenerate graph H on n vertices. We show that for such graphs r(H) \leq 2^{c_d\sqrt{\log n}}n, improving on an earlier bound of Kostochka and Sudakov. We also study Ramsey numbers of random graphs, showing that for d fixed, almost surely the random graph G(n,d/n) has Ramsey number linear in n. For random bipartite graphs, our proof gives nearly tight bounds.

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Jacob Fox, Benny Sudakov. 2008-03-12. Two remarks on the Burr-Erdos conjecture. https://arxiv.org/abs/0803.1860

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