Sets and subsets!
Source: Romania TST 2014 Day 1 Problem 5
January 21, 2015
combinatorics unsolvedcombinatorics
Problem Statement
Let be an integer greater than and let be a finite set containing more than elements.Consider the collection of all sets of subsets of satisfying the following two conditions :
(a) Each member of contains at least elements of .
(b) Each element of is contained in at least members of .Determine , as runs through all subsets of whose members cover , and runs through the above collection.