For a simple finite graph G let C-o(G) and C-e(G) denote the set of odd cycle lengths and even cycle lengths in a graph G, respectively. We will show that the chromatic number chi(G) of G satisfies: chi(G) less than or equal to min {2r + 2,2s + 3} less than or equal to r + s + 2, if \Co(G)\ = r and \Ce(G)\ = s. (C) 2004 Elsevier B.V. All rights reserved.
机构:
Department of Pure Mathematics and Mathematical Statistics (DPMMS), University of Cambridge, Wilberforce Road, Cambridge,CB3 0WA, United KingdomDepartment of Pure Mathematics and Mathematical Statistics (DPMMS), University of Cambridge, Wilberforce Road, Cambridge,CB3 0WA, United Kingdom
机构:
Univ Cambridge, Dept Pure Math & Math Stat DPMMS, Wilberforce Rd, Cambridge CB3 0WA, EnglandUniv Cambridge, Dept Pure Math & Math Stat DPMMS, Wilberforce Rd, Cambridge CB3 0WA, England