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Research notes on every problem, and a library of the papers behind them. Built from the open erdos repository.

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Claim. Theorem 1 (p. 313) of P. Erdős, R. J. Faudree, C. C. Rousseau and R. H. Schelp, Multipartite graph--sparse graph Ramsey numbers, Combinatorica 5 (1985), no. 4, 311--318: given s=p1≤⋯≤pms=p_1\le\cdots\le p_m, kk and Δ\Delta, there is n0n_0 such that every connected graph GG on n>n0n>n_0 vertices with at most n+kn+k edges and maximum degree at most Δ\Delta satisfies

r(K(p1,…,pm),G)=(m−1)(n−1)+s.r(K(p_1,\ldots,p_m),G)=(m-1)(n-1)+s.

A tree on nn vertices has n−1n-1 edges, so the theorem applies to every tree of maximum degree at most Δ\Delta once nn is large in terms of Δ\Delta and the class sizes. In the letters of Problem 550, applied to both sides, it gives R(T,Km1,…,mk)=(k−1)(n−1)+m1R(T,K_{m_1,\dots,m_k})=(k-1)(n-1)+m_1 and R(T,Km1,m2)=n−1+m1R(T,K_{m_1,m_2})=n-1+m_1, so the right side of the inequality is (k−1)(n−2+m1)+m1≥(k−1)(n−1)+m1(k-1)(n-2+m_1)+m_1\ge(k-1)(n-1)+m_1 and the inequality holds. The paper does not state the problem's inequality; its statements are recorded on the library home erdos_1985_multipartite_graph_sparse_graph_ramsey_numbers.

Covers. For fixed kk, m1≤⋯≤mkm_1\le\dots\le m_k and Δ\Delta, every tree on nn vertices with maximum degree at most Δ\Delta, once nn exceeds a bound depending on Δ\Delta and the mim_i. Trees whose maximum degree grows with nn are outside it.

Depends on. Nothing in this wiki; the theorem and its proof are the paper's own.

Acceptance. Refereed: the paper is a journal publication in Combinatorica, volume 5, number 4 (December 1985), received 4 March 1983, the refereed evidence; the issue carries no day, so this page is dated to the first day of that month. It is the site's source key for the problem, but the site's label OPEN (LEAN) settles neither the problem nor a declared part of it, so reviewed is not listed. The proof is cited at statement depth.