Flexible coinductive logic programming. Issue 6 (November 2020)

• Record Type: Journal Article
• Authors: DAGNINO, FRANCESCO; ANCONA, DAVIDE; ZUCCA, ELENA
• Is Part Of: Theory and practice of logic programming. Volume 20:Issue 6(2020)
• Page Start: 818
• Page End: 833
• Publication Date: 2020-11
• Subjects: coinduction, -- operational semantics, -- declarative semantics, -- soundness, -- completeness; Logic programming -- Periodicals; Artificial intelligence -- Computer programs -- Periodicals; Constraint programming (Computer science) -- Periodicals; 005.115
• DOI: 10.1017/S147106842000023X
• Languages: English
• ISSNs: 1471-0684

Abstract

Abstract: Recursive definitions of predicates are usually interpreted either inductively or coinductively. Recently, a more powerful approach has been proposed, called flexible coinduction, to express a variety of intermediate interpretations, necessary in some cases to get the correct meaning. We provide a detailed formal account of an extension of logic programming supporting flexible coinduction. Syntactically, programs are enriched by coclauses, clauses with a special meaning used to tune the interpretation of predicates. As usual, the declarative semantics can be expressed as a fixed point which, however, is not necessarily the least, nor the greatest one, but is determined by the coclauses. Correspondingly, the operational semantics is a combination of standard SLD resolution and coSLD resolution. We prove that the operational semantics is sound and complete with respect to declarative semantics restricted to finite comodels.