The class of decision problems solvable by an NP machine such that
Defined in [FFK94], where it was also shown that LWPP is low for PP and C=P. (I.e. adding LWPP as an oracle does not increase the power of these classes.)
Contains SPP.
Also, contains the graph isomorphism problem [KST92].
Contains a whole litter of problems for solvable black-box groups: group intersection, group factorization, coset intersection, and double-coset membership [Vin04].
The class of decision problems solvable by an NP machine such that for some polynomial-time computable (i.e. FP) function f,
Defined in [FFK94].
Contains BQP [FR98], WAPP [BGM02], LWPP, and WPP.
The same as BQP, except that the quantum algorithm must return the correct answer with probability 1, and run in polynomial time with probability 1. Unlike bounded-error quantum computing, there is no theory of universal QTMs for exact quantum computing models. In the original definition in [BV97], each language in EQP is computed by a single QTM, equivalently to a uniform family of quantum circuits with a finite gate set K whose amplitudes can be computed in polynomial time. See EQPK. However, some results require an infinite gate set. The official definition here is that the gate set should be finite.
Without loss of generality, the amplitudes in the gate set K are algebraic numbers [ADH97].
There is an oracle that separates EQP from NP [BV97], indeed from Δ2P [GP01]. There is also an oracle relative to which EQP is not in ModpP where p is prime [GV02]. On the other hand, EQP is in LWPP [FR98].
P||NP[2k] is contained in EQP||NP[k], where "||NP[k]" denotes k nonadaptive oracle queries to NP (queries that cannot depend on the results of previous queries) [BD99].
See also ZBQP.
The set of problems that can be answered by a uniform family of polynomial-sized quantum circuits whose gates are drawn from a set K, and that return the correct answer with probability 1, and run in polynomial time with probability 1, and the allowed gates are drawn from a set K. K may be either finite or countable and enumerated. If S is a ring, the union of EQPK over all finite gate sets K whose amplitudes are in the ring R can be written EQPS.
Defined in [ADH97] in the special case of a finite set of 1-qubit gates controlled by a second qubit. It was shown there that transcendental gates may be replaced by algebraic gates without decreasing the size of EQPK.
[FR98] show that EQPQ is in LWPP. The proof can be generalized to any finite, algebraic gate set K.
The hidden shift problem for a vector space over Z/2 is in EQPQ by Simon's algorithm. The discrete logarithm problem over Z/p is in EQPQ-bar using infinitely many gates [MZ03].
The class of decision problems solvable by an NP machine such that
We may additionally require that all paths make the same number of binary nondeterministic choices, but then the second condition has to be modified so that if the answer is "yes", the number of accepting and rejecting paths differ by 2. (If the total number of paths is even then the numbers can't differ by 1.)
Defined in [FFK94], where it was also shown that SPP is low for PP, C=P, ModkP, and SPP itself. (I.e. adding SPP as an oracle does not increase the power of these classes.)
Independently defined in [OH93], who called the class XP.
Contained in LWPP, C=P, and WPP among other classes.
Contains FewP; indeed, FewP is low for SPP, so that SPPFewP = SPP [FFK94].
Contains the problem of deciding whether a graph has any nontrivial automorphisms [KST92].
Indeed, contains graph isomorphism [AK02].
Contains a whole gaggle of problems for solvable black-box groups: solvability testing, membership testing, subgroup testing, normality testing, order verification, nilpotetence testing, group isomorphism, and group intersection [Vin04]
[AK02] also showed that the Hidden Subgroup Problem for permutation groups, of interest in quantum computing, is in FPSPP.
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.