Same as SBP, except that f is a nonnegative-valued GapP function rather than a #P function.
Defined in [Vya03], where the following was also shown:
Kuperberg ([Kup09]) showed that A0PP = SBQP.
The class of decision problems solvable by a QTM in polynomial time such that a particular '|Accept>' state has nonzero amplitude at the end of the computation, if and only if the answer is 'yes.' Since it has an exact amplitude condition, NQP has the same technical caveats as EQP. Or it would, except that it turns out to equal coC=P [FGH+98].
Defined in [ADH97].
Contrast with QMA.
The class of decision problems solvable by an NP machine such that
Defined in [FFK94].
Contained in C=P ∩ coC=P, as well as AWPP.