Constructing fair sports league schedules with regard to strength groups

A single round robin tournament (SRRT) consists of nn teams and a set of periods. Matches between the teams have to be scheduled such that each team plays against each other team exactly once and each team plays at most once per period. In order to establish fairness among teams, we consider a partition of the teams into strength groups. Then, the goal is to avoid matches where a team plays against extremely weak or extremely strong teams in consecutive periods. In this paper, we pick up two concepts ensuring different degrees of fairness and address several questions which remained open so far.