Temporal logic programs with variables*. Issue 2 (11th November 2016)

• Record Type: Journal Article
• Authors: AGUADO, FELICIDAD; CABALAR, PEDRO; PÉREZ, GILBERTO; VIDAL, CONCEPCIÓN; DIÉGUEZ, MARTÍN
• Is Part Of: Theory and practice of logic programming. Volume 17:Issue 2(2017)
• Page Start: 226
• Page End: 243
• Publication Date: 2016-11-11
• Subjects: artificial intelligence, -- knowledge representation, -- temporal logic, -- grounding, -- logic programming, -- answer set programming; Logic programming -- Periodicals; Artificial intelligence -- Computer programs -- Periodicals; Constraint programming (Computer science) -- Periodicals; 005.115
• DOI: 10.1017/S1471068416000570
• Languages: English
• ISSNs: 1471-0684

Abstract

Abstract: In this note, we consider the problem of introducing variables in temporal logic programs under the formalism of Temporal Equilibrium Logic, an extension of Answer Set Programming for dealing with linear-time modal operators. To this aim, we provide a definition of a first-order version of Temporal Equilibrium Logic that shares the syntax of first-order Linear-time Temporal Logic but has different semantics, selecting some Linear-time Temporal Logic models we call temporal stable models . Then, we consider a subclass of theories (called splittable temporal logic programs ) that are close to usual logic programs but allowing a restricted use of temporal operators. In this setting, we provide a syntactic definition of safe variables that suffices to show the property of domain independence – that is, addition of arbitrary elements in the universe does not vary the set of temporal stable models. Finally, we present a method for computing the derivable facts by constructing a non-temporal logic program with variables that is fed to a standard Answer Set Programming grounder. The information provided by the grounder is then used to generate a subset of ground temporal rules which is equivalent to (and generally smaller than) the full program instantiation.