When scheduling a round robin tournament (RRT) a Home-Away-Pattern (HAP) set defines for each team i and each period p whether i plays at home or away in p. So far the complexity of the decision problem whether a RRT can be arranged based on a given HAP set or not is open. We give a necessary...

A single round robin tournament (RRT) consists of a set T of n teams (n even) and a set P of n - 1 periods. The teams have to be scheduled such that each team plays exactly once against each other team and such that each team plays exactly once per period. In order to establish fairness among...