TOT 111 1986 Spring J5 20 football teams in a tournament
Source:
August 29, 2019
Tournamentcombinatorics
Problem Statement
football teams take part in a tournament . On the first day all the teams play one match . On the second day all the teams play a further match . Prove that after the second day it is possible to select teams, so that no two of them have yet played each other.( S . A . Genkin)