17 research outputs found

    The list-chromatic index of K 6

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    We prove that the list-chromatic index and paintability index of K"6 is 5. That indeed @g"@?^'(K"6)=5 was a still open special case of the List Coloring Conjecture. Our proof demonstrates how colorability problems can numerically be approached by the use of computer algebra systems and the Combinatorial Nullstellensatz

    A note on total and list edge-colouring of graphs of tree-width 3

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    It is shown that Halin graphs are Δ\Delta-edge-choosable and that graphs of tree-width 3 are (Δ+1)(\Delta+1)-edge-choosable and (Δ+2)(\Delta +2)-total-colourable.Comment: arXiv admin note: substantial text overlap with arXiv:1504.0212

    Some results on (a:b)-choosability

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    A solution to a problem of Erd\H{o}s, Rubin and Taylor is obtained by showing that if a graph GG is (a:b)(a:b)-choosable, and c/d>a/bc/d > a/b, then GG is not necessarily (c:d)(c:d)-choosable. Applying probabilistic methods, an upper bound for the kthk^{th} choice number of a graph is given. We also prove that a directed graph with maximum outdegree dd and no odd directed cycle is (k(d+1):k)(k(d+1):k)-choosable for every k≥1k \geq 1. Other results presented in this article are related to the strong choice number of graphs (a generalization of the strong chromatic number). We conclude with complexity analysis of some decision problems related to graph choosability

    List-Edge-Coloring Triangulations with Maximum Degree 5

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    We prove that triangulations with maximum degree 5 are 6-list-edge-colorable
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