MathDB

A set with 2006 elements and intersection of subsets

Source: Romanian JBMO TST 2006, Day 4, Problem 1

May 19, 2006

Problem Statement

Let

A=\{1,2,\ldots, 2006\}

. Find the maximal number of subsets of

A

that can be chosen such that the intersection of any 2 such distinct subsets has 2004 elements.