Constructions via Hamiltonian Theorems

Demetrovics et al [Design type problems motivated by database theory, J. Statist. Plann. Inference 72 (1998) 149-164] constructed a decomposition of the family of all k-element subsets of an n-element set into disjoint pairs (A,B)(A∩B=∅,|A|=|B|=k) where two such pairs are relatively far from each other in some sense. The paper invented a proof method using a Hamiltonian-type theorem. The present paper gives a generalization of this tool, hopefully extending the power of the method. Problems where the method could be also used are shown. Moreover, open problems are listed which are related to the Hamiltonian theory. In these problems a cyclic permutation is to be found when certain restrictions are given by a family of k-element subsets.