The class of decision problems for which there exists a polynomial-time quantum algorithm that accepts with probability at least 2−p(n) if the answer is "yes", and with probability at most 2−p(n)−1 if the answer is "no", for some polynomial p.
Defined by Kuperberg in [Kup09], where he showed that SBQP = A0PP.
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.