It is known that if an algebra of polymorphisms of the constraint language has the Polynomially Generated Powers (PGP) Property then the Quantified CSP can be reduced to the CSP over the same constraint language with constants. The only limitation of this reduction is that it is applicable only for the constraint languages with constants. We drastically simplified the reduction and generalized it for constraint languages without constants. As a result, we completely classified the complexity of the QCSP for constraint languages having the PGP property.
翻译:众所周知,如果约束语言多形态的代数具有多种族生成力特性,那么量化的CSP可以与固定不变的同一约束语言压缩到CSP, 唯一的限制是,这一减少只适用于有常数的制约语言。我们大幅度简化了限制语言的缩放,并将其推广到没有常数的制约语言。因此,我们完全区分了QCSP的复杂性,以限制具有PGP属性的语言。