I would like to define a set for two sets $A$ and $B$ such that:
$$ \{x: \{x \in A\} \neq \emptyset \ \ \cap \ \ \{x \in B\}\neq \emptyset \} $$
That is, I would like find the collection of events $x$ that are simultaneously not the empty set under both $A$ and $B$. Is there a more elegant way to write this?