Two results on the digraph chromatic number
نویسندگان
چکیده
منابع مشابه
Two results on the digraph chromatic number
It is known (Bollobás [4]; Kostochka and Mazurova [13]) that there exist graphs of maximum degree ∆ and of arbitrarily large girth whose chromatic number is at least c∆/ log ∆. We show an analogous result for digraphs where the chromatic number of a digraph D is defined as the minimum integer k so that V (D) can be partitioned into k acyclic sets, and the girth is the length of the shortest cyc...
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ژورنال
عنوان ژورنال: Discrete Mathematics
سال: 2012
ISSN: 0012-365X
DOI: 10.1016/j.disc.2012.01.028