We give an AC0 upper bound on the complexity of rst-oder queries over (in nite) databases de ned by restricted linear constraints. This result enables us to deduce the non-expressi...
We study the expressibility problem: given a finite constraint language Γ on a finite domain and another relation R, can Γ express R? We prove, by an explicit family of example...
We rework parts of the classical relational theory when the underlying domain is a structure with some interpreted operations that can be used in queries. We identify parts of the...
Non-deterministic operators are needed in First-Order relational languages and Datalog to extend the expressive power of such languages and support efficient formulations of lowco...