biribol tournament
Source: Iberoamerican Olympiad 2008, problem 6
September 25, 2008
inductioncombinatorics proposedcombinatorics
Problem Statement
Biribol is a game played between two teams of 4 people each (teams are not fixed). Find all the possible values of for which it is possible to arrange a tournament with players in such a way that every couple of people plays a match in opposite teams exactly once.