Hungary-Israel Binational 1994_4
Source:
October 29, 2008
group theoryabstract algebrapigeonhole principlecombinatorics unsolvedcombinatorics
Problem Statement
An n\minus{}m society is a group of girls and boys. Prove that there exists numbers and such that every n_0\minus{}m_0 society contains a subgroup of five boys and five girls with the following property: either all of the boys know all of the girls or none of the boys knows none of the girls.