b-coloring of Kneser graphs

  • Authors:
  • R. Balakrishnan;T. Kavaskar

  • Affiliations:
  • Department of Mathematics, Bharathidasan University, Tiruchirappalli-620024, India;Department of Mathematics, B. S. Abdur Rahman University, Chennai-600048, India

  • Venue:
  • Discrete Applied Mathematics
  • Year:
  • 2012

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Abstract

A b-coloring of a graph G with k colors is a proper coloring of G using k colors in which each color class contains a color dominating vertex, that is, a vertex which has a neighbor in each of the other color classes. The largest positive integer k for which G has a b-coloring using k colors is the b-chromatic number b(G) of G. The b-spectrum S"b(G) of a graph G is the set of positive integers k,@g(G)@?k@?b(G), for which G has a b-coloring using k colors. A graph G is b-continuous if S"b(G) = the closed interval [@g(G),b(G)]. In this paper, we obtain an upper bound for the b-chromatic number of some families of Kneser graphs. In addition we establish that [@g(G),n+k+1]@?S"b(G) for the Kneser graph G=K(2n+k,n) whenever 3@?n@?k+1. We also establish the b-continuity of some families of regular graphs which include the family of odd graphs.