The b-continuity of graphs with large girth
Abstract
A b-coloring of a graph is a proper coloring such that each color class has at least one vertex which is adjacent to each other color class. The b-spectrum of G is the set Sb(G) of integers k such G has a b-coloring with k colors and b(G) = maxSb(G) is the b-chromatic number of G. A graph is b-continous if Sb(G) = |X(G), b(G)| ∩ Z. An infinite number of graphs that are not b-continuous is known. Also it is known that graphs with girth at least 10 are b-continuous. In this article, we prove that graphs with girth at least 8 are b-continuous and that the b-spectrum of graphs with girth at least 7 contains the integers between 2X(G) and b(G).
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