The exponential-time analogue of MIP.
In the unrelativized world, equals NEEXP.
There exists an oracle relative to which MIPEXP equals the intersection of P/poly, PNP, and ⊕P [BFT98].
Nondeterministic double-exponential time (i.e. NTIME(22p(n)) for p a polynomial).
Equals MIPEXP (unrelativized).