  The set equality problem is to tell whether two sets $A$ and $B$ are equal or
disjoint under the promise that one of these is the case. This problem is
related to the Graph Isomorphism problem. It was an open problem to find any
$\omega(1)$ query lower bound when sets $A$ and $B$ are given by quantum
oracles. We will show that any error-bounded quantum query algorithm that
solves the set equality problem must evaluate oracles
$\Omega(\sqrt[5]{\frac{n}{\ln n}})$ times, where $n=|A|=|B|$.
