Quantum and classical complexity classes: Separations, collapses, and closure properties

It is shown that relative to an oracle, ZPP is not contained in WPP, which implies that no relativizable proof technique can improve the best known classical upper bound for BQP (BQP ⊆ AWPP [16]) to WPP and the bestknown classical lower bound for EQP (P⊆ EQP) to ZPP ⊁ EQP.