 Every language in NP also belongs to For by definition, a language "L" is in NP, if and only if there exists a polynomial-time verifier "V"("x","y"), such that for every "x" in "L" there exists "y" for which "V" answers true, and such that for every "x" not in "L", "V" always answers false.But such a verifier can easily be transformed into an predicate "P"("x","y","z") for the same language that ignores "z" and otherwise behaves the same as "V".By the same token, co-NP belongs to These straightforward inclusions can be strengthened to show that the class contains MA (by a generalization of the Sipser–Lautemann theorem) and formula_9 (more generally, formula_10).