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Comment.Math.Univ.Carolinae 42,2 (2001) 353-355.
Abstract: One consequence of Hedetniemi’s conjecture on the chromatic number of the product of graphs is that the boundχ(G×H)≥min{χf(G), χf(H)}should always hold. We prove thatχ(G×H)≥ 12min{χf(G), χf(H)}.
Keywords: Hedetniemi’s conjecture, (fractional) chromatic number AMS Subject Classification: 05C15
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