0641 n subsets of a set with 5 elements 6th edition Round 4 p1
Source:
May 3, 2021
combinatoricsSets
Problem Statement
Let be a family of n subsets of a set with elements, such that any two subsets in have a common element. Find the minimal value of such that no matter how we choose with the properties above, there exists exactly one element of which belongs to all the sets in .