M. Ghasemi Received: June 5, 2013; Revised: January 23, 2014; Accepted: March 10, 2014 Abstract. A regular cover of a connected graph is called dihedral if its transformation group is dihedral. In this paper the author classifies all dihedral coverings of the complete graph K5 whose fibre-preserving automorphism subgroups act arc-transitively. Keywords: symmetric graphs; s-regular graphs; regular coverings. AMS Subject classification: Primary: 05C25, 20B25 Version to read: PDF 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 © 2014, ACTA MATHEMATICA UNIVERSITATIS COMENIANAE |