3 research outputs found

    Colored complete hypergraphs containing no rainbow Berge triangles

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    The study of graph Ramsey numbers within restricted colorings, in particular forbidding a rainbow triangle, has recently been blossoming under the name Gallai-Ramsey numbers. In this work, we extend the main structural tool from rainbow triangle free colorings of complete graphs to rainbow Berge triangle free colorings of hypergraphs. In doing so, some other concepts and results are also translated from graphs to hypergraphs

    Monochromatic kk-connected Subgraphs in 2-edge-colored Complete Graphs

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    Bollob\'{a}s and Gy\'{a}rf\'{a}s conjectured that for any k,n∈Z+k, n \in \mathbb{Z}^+ with n>4(kβˆ’1)n > 4(k-1), every 2-edge-coloring of the complete graph on nn vertices leads to a kk-connected monochromatic subgraph with at least nβˆ’2k+2n-2k+2 vertices. We find a counterexample with n=5kβˆ’2⌈2kβˆ’1βŒ‰βˆ’3n = 5k-2\lceil\sqrt{2k-1}\rceil-3, thus disproving the conjecture, and we show the conjecture is true for nβ‰₯5kβˆ’min⁑{4kβˆ’2+3,0.5k+4}n \ge 5k-\min\{\sqrt{4k-2}+3, 0.5k+4\}
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