Testing Strong Equivalence of Datalog Programs - Implementation and Examples

In this work we describe a system for determining strong equivalence of disjunctive non-ground datalog programs under the stable model semantics. The problem is tackled by reducing it to the unsatisfiability problem of first-order formulas in the Bernays-Schonfinkel fragment. We then employ a tableaux-based theorem prover, which (unlike most other currently available provers) is guaranteed to terminate for these formulas. To the best of our knowledge, this is the first strong equivalence tester for disjunctive non-ground datalog.