eight different symbols
Source: 8-th Taiwanese Mathematical Olympiad 1999
January 22, 2007
inductioncombinatorics unsolvedcombinatorics
Problem Statement
There are eight different symbols designed on different T-shirts. Each shirt contains at least one symbol, and no two shirts contain all the same symbols. Suppose that for any symbols the number of shirts containing at least one of the symbols is even. Determine the value of .