[2GF] Find a non-empty set of indexes \(I\), and, for each \(i∈ I\), non-empty sets \(A_ i\), so that there does not exists a subset \(B\) of \(⋃_{i∈ I}A_ i\) with the property that, for each \(i∈ I\), \(B∩ A_ i\) contains a single element.
[2GG]↺↻