On the power of stratified logic programs with value invention for expressing database transformations

Abstract

The expressive power of the family of ILOG(⌝) languages is investigated. The languages are rule based, with value invention and stratified negation. The chosen semantics for value invention is based on Skolem functor terms. We show that, in presence of value invention, the whole expressive power is achieved using programs made of two strata, and that ILOG≠ (i.e., the class of programs with non-equality and without negation) express the downward monotone list constructive transformations.