The probabilistic analogue of YP; it is to YP what MA is to NP. Formally, the class of decision problems for which there exists a syntactic BPP machine M such that:
To amplify a YPP machine, one can run it multiple times, then accept if a majority of runs accept, reject if a majority reject, and otherwise output "I don't know."
Contains BPP and YP, and is contained in MA and P/poly.
The class of decision problems for which there exists a polynomial-time machine M such that:
Defined in a recent post of the blog Shtetl-Optimized. See there for an explanation of the class's name.
Contains ZPP by the same argument that places BPP in P/poly.
Also contains P with TALLY ∩ NP ∩ coNP oracle.
Is contained in NP ∩ coNP and YPP.
Is equal to ONP ∩ coONP.
Is to YPP as BQP is to BPP, and QMA is to MA. The machine is now a quantum computer and the advice is a quantum state |ψ_n>.
Contains BQP and YPP, and is contained in QMA and BQP/qpoly.