2-perfect M-cycle Systems

Abstract The spectrum for 2-perfect m -cycle systems of K n has been considered by several authors in the case when m ⩽7. In this paper we essentially solve the problem for 2-perfect m -cycle systems of K n in the case where m is prime and 2 m +1 is a prime power. In particular we settle the problem for m = 11 and 13 except for two or one possible exceptions respectively. The problem for m = 9 is also considered.