On Signings and the Well-Founded Semantics. Issue 1 (20th January 2022)

• Record Type: Journal Article
• Authors: MAHER, MICHAEL J.
• Is Part Of: Theory and practice of logic programming. Volume 22:Issue 1(2022)
• Page Start: 115
• Page End: 127
• Publication Date: 2022-01-20
• Subjects: signing -- well-founded semantics -- query optimization; Logic programming -- Periodicals; Artificial intelligence -- Computer programs -- Periodicals; Constraint programming (Computer science) -- Periodicals; 005.115
• DOI: 10.1017/S1471068421000077
• Languages: English
• ISSNs: 1471-0684

Abstract

Abstract: In this note, we use Kunen's notion of a signing to establish two theorems about the well-founded semantics of logic programs, in the case where we are interested in only (say) the positive literals of a predicate p that are consequences of the program. The first theorem identifies a class of programs for which the well-founded and Fitting semantics coincide for the positive part of p . The second theorem shows that if a program has a signing, then computing the positive part of p under the well-founded semantics requires the computation of only one part of each predicate. This theorem suggests an analysis for query answering under the well-founded semantics. In the process of proving these results, we use an alternative formulation of the well-founded semantics of logic programs, which might be of independent interest.