80 research outputs found

    Improved Delsarte bounds for spherical codes in small dimensions

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    We present an extension of the Delsarte linear programming method. For several dimensions it yields improved upper bounds for kissing numbers and for spherical codes. Musin's recent work on kissing numbers in dimensions three and four can be viewed in our framework.Comment: 16 pages, 3 figures. Substantial changes after referee's comments, one new lemm

    Total weight choosability in Hypergraphs

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    A total weighting of the vertices and edges of a hypergraph is called vertex-coloring if the total weights of the vertices yield a proper coloring of the graph, i.e., every edge contains at least two vertices with different weighted degrees. In this note we show that such a weighting is possible if every vertex has two, and every edge has three weights to choose from, extending a recent result on graphs to hypergraphs
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