论文信息 - Dichromatic number, circulant tournaments and Zykov sums of digraphs

Dichromatic number, circulant tournaments and Zykov sums of digraphs

The dichromatic number dc(D) of a digraph D is the smallest number of colours needed to colour the vertices of D so that no monochromatic directed cycle is created. In this paper the problem of computing the dichromatic number of a Zykov-sum of digraphs over a digraph D is reduced to that of computing a multicovering number of an hypergraph H1(D) associated to D in a natural way. This result allows us to construct an infinite family of pairwise non isomorphic vertex-critical k-dichromatic circulant tournaments for every k ≥ 3, k 6= 7.

Victor Neumann-Lara | V. Neumann-Lara

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