An example of this is the complexity class defined from the existential theory of the reals, a computational problem that is known to be NP-hard and in PSPACE, but is not known to be complete for NP, PSPACE, or any language in the polynomial hierarchy. is the set of problems having a polynomial-time many-one reduction to the existential theory of the reals; it has several other complete problems such as determining the rectilinear crossing number of an undirected graph. Each problem in inherits the property of belonging to PSPACE, and each -complete problem is NP-hard..
An example of this is the complexity class defined from the existential the?ory of the reals, a computational problem that is known to be NP-hard and in PSPACE, but is not known to be complete for NP, PSPACE, or any language in the polynomial hierarchy. is the set of problems having a polynomial-time many-one reduction to the existential theory of the reals; it has several other complete problems such as determining the rectilinear crossing number of an !undirected graph. Each problem in inherits the property of belonging to PSPACE, and each -complete problem is NP-hard..