IMO 1986 LL ROM61

Given a positive integer n, find the greatest integer p with the

imolonglistmathematicsolympiad

IMO 1986 LL ROM61

Origin: ROM

Problem

Given a positive integer n, find the greatest integer p with the property that for any function f : P(X) \toC, where X and C are sets of cardinality n and p, respectively, there exist two distinct sets A, B \inP(X) such that f(A) = f(B) = f(A \cupB). (P(X) is the family of all subsets of X.)