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Density and power graphs in graph homomorphism problem

Daneshgar, A ; Sharif University of Technology | 2008

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  1. Type of Document: Article
  2. DOI: 10.1016/j.disc.2007.07.090
  3. Publisher: 2008
  4. Abstract:
  5. We introduce two necessary conditions for the existence of graph homomorphisms based on the concepts of density and power graph. As corollaries, we obtain a lower bound for the fractional chromatic number, and we set forward elementary proofs of the facts that the circular chromatic number of the Petersen graph is equal to three and the fact that the Coxeter graph is a core. © 2007 Elsevier B.V. All rights reserved
  6. Keywords:
  7. Density (specific gravity) ; Number theory ; Problem solving ; Theorem proving ; Graph homomorphism ; Pentagon conjecture ; Power graph ; Graph theory
  8. Source: Discrete Mathematics ; Volume 308, Issue 17 , 6 September , 2008 , Pages 4027-4030 ; 0012365X (ISSN)
  9. URL: https://www.sciencedirect.com/science/article/pii/S0012365X07005857