Sending non-intersecting teams to an olympiad
Source: Tuymaada 2018 Senior League/Problem 7
July 20, 2018
combinatorics
Problem Statement
A school has three senior classes of students each. Every student knows at least people in each of the other two classes. Prove that the school can send non-intersecting teams to the olympiad so that each team consists of students from different classes who know each other.Proposed by C. Magyar, R. Martin