The flexibility of home away pattern sets

A popular approach to construct a schedule for a round-robin tournament is known as first-break, then-schedule. Thus, when given a home away pattern (HAP) for each team, which specifies for each round whether the team plays a home game or an away game, the remaining challenge is to find a round for each match that is compatible with both team’s patterns. When using such an approach, it matters how many rounds are available for each match: the more rounds are available for a match, the more options exist to accommodate particular constraints. We investigate the notion of flexibility of a set of HAPs and introduce a number of measures assessing this flexibility. We show how the so-called canonical pattern set (CPS) behaves on these measures, and, by solving integer programs, we give explicit values for all single-break HAP sets with at most 16 teams.