332 research outputs found

    A General Lower Bound on Gallai-Ramsey Numbers for Non-Bipartite Graphs

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    Given a graph HH and a positive integer kk, the kk-color Gallai-Ramsey number grk(K3:H)gr_{k}(K_{3} : H) is defined to be the minimum number of vertices nn for which any kk-coloring of the complete graph KnK_{n} contains either a rainbow triangle or a monochromatic copy of HH. The behavior of these numbers is rather well understood when HH is bipartite but when HH is not bipartite, this behavior is a bit more complicated. In this short note, we improve upon existing lower bounds for non-bipartite graphs HH to a value that we conjecture to be sharp up to a constant multiple

    Density of Gallai Multigraphs

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    Diwan and Mubayi asked how many edges of each color could be included in a 33-edge-colored multigraph containing no rainbow triangle. We answer this question under the modest assumption that the multigraphs in question contain at least one edge between every pair of vertices. We also conjecture that this assumption is, in fact, without loss of generality
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