p. 21 - 28 Dirichlet Character Difference Graphs M. Budden, N. Calkins, W. N. Hack, J. Lambert and K. Thompson Received: October 3, 2011; Revised: November 5, 2012; Accepted: November 5, 2012 Abstract. We define Dirichlet character difference graphs and describe their basic properties, including the enumeration of triangles and edge-disjoint hamiltonian cycles. In the case where the modulus is an odd prime, we exploit the spectral properties of such graphs in order to provide meaningful upper bounds for their diameter. Keywords: Cayley graphs; Paley graphs; circulant matrices. AMS Subject classification: Primary: 05C38, 05C12 Secondary: 05C50, 11T24, 11R18 PDF Compressed Postscript Version to read ISSN 0862-9544 (Printed edition) Faculty of Mathematics, Physics and Informatics Comenius University 842 48 Bratislava, Slovak Republic Telephone: + 421-2-60295111 Fax: + 421-2-65425882 e-Mail: amuc@fmph.uniba.sk Internet: www.iam.fmph.uniba.sk/amuc © 2013, ACTA MATHEMATICA UNIVERSITATIS COMENIANAE |