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Strongly Projective Graphs

Published online by Cambridge University Press:  20 November 2018

Benoit Larose
Benoit Larose*
Affiliation:
Department of Mathematics, Champlain Regional College, 900 Riverside St-Lambert, Quebec, J4P 3P2 Department of Mathematics and Statistics, Concordia University, 1455 de Maisonneuve West Montréal, Quebec, H3G 1M8, e-mail: larose@mathstat.concordia.ca
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Abstract

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We introduce the notion of strongly projective graph, and characterise these graphs in terms of their neighbourhood poset. We describe certain exponential graphs associated to complete graphs and odd cycles. We extend and generalise a result of Greenwell and Lovász [6]: if a connected graph $G$ does not admit a homomorphism to $K$ , where $K$ is an odd cycle or a complete graph on at least 3 vertices, then the graph $G\,\times \,{{K}^{S}}$ admits, up to automorphisms of $K$ , exactly $s$ homomorphisms to $K$ .

Keywords

05C1506A99

Information

Type
Research Article
Information
Canadian Journal of Mathematics , Volume 54 , Issue 4 , 01 August 2002 , pp. 757 - 768
Copyright
Copyright © Canadian Mathematical Society 2002

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