# Smallest problem set for “sufficiently distinct” exam papers

Given a set of sets $$\{A_i\}$$, $$\forall i,j, |A_i|=N, |A_i\cap A_j|\leq M$$. What is the smallest possible $$\left|\cup_i A_i\right|$$?

• N. Further N <= M. – William Elliot Sep 18 at 5:23