Tight Semantics for Logic Programs

Luis Moniz Pereira & Alexandre Miguel Pinto
We define the Tight Semantics (TS), a new semantics for all NLPs complying with the requirements of: 2-valued semantics; preserving the models of SM; guarantee of model existence, even in face of Odd Loops Over Negation (OLONs) or infinite chains; relevance cumulativity; and compliance with the Well-Founded Model. When complete models are unnecessary, and top-down querying (à la Prolog) is desired, TS provides the 2-valued option that guarantees model existence, as a result of its...