The empty set is a member of $P(\{a,b\}) \times P(\{p,q\})$. True or false?
My first instinct was false, since the empty set is a member of each power set individually, but when multiplied together, you get $(\emptyset,\emptyset)$, which I'm not sure represents the empty set. But my counter argument is that the empty set is a member of the power set of anything, right?