Anytime answer set optimization via unsatisfiable core shrinking. Issue 5 (14th October 2016)

• Record Type: Journal Article
• Authors: ALVIANO, MARIO; DODARO, CARMINE
• Editors: Carro, Manuel; King, Andy
• Is Part Of: Theory and practice of logic programming. Volume 16:Issue 5/6(2016)
• Page Start: 533
• Page End: 551
• Publication Date: 2016-10-14
• Subjects: answer set programming, -- weak constraints, -- unsatisfiable cores; Logic programming -- Periodicals; Artificial intelligence -- Computer programs -- Periodicals; Constraint programming (Computer science) -- Periodicals; 005.115
• DOI: 10.1017/S147106841600020X
• Languages: English
• ISSNs: 1471-0684

Abstract

Abstract: Unsatisfiable core analysis can boost the computation of optimum stable models for logic programs with weak constraints. However, current solvers employing unsatisfiable core analysis either run to completion, or provide no suboptimal stable models but the one resulting from the preliminary disjoint cores analysis. This drawback is circumvented here by introducing a progression based shrinking of the analyzed unsatisfiable cores. In fact, suboptimal stable models are possibly found while shrinking unsatisfiable cores, hence resulting into an anytime algorithm. Moreover, as confirmed empirically, unsatisfiable core analysis also benefits from the shrinking process in terms of solved instances.