Founded (Auto)Epistemic Equilibrium Logic Satisfies Epistemic Splitting. Issue 5 (September 2019)

• Record Type: Journal Article
• Authors: FANDINNO, JORGE
• Is Part Of: Theory and practice of logic programming. Volume 19:Issue 5/6(2019)
• Page Start: 671
• Page End: 687
• Publication Date: 2019-09
• Subjects: Answer Set Programming, -- Epistemic Specifications, -- Epistemic Logic Programs; Logic programming -- Periodicals; Artificial intelligence -- Computer programs -- Periodicals; Constraint programming (Computer science) -- Periodicals; 005.115
• DOI: 10.1017/S1471068419000127
• Languages: English
• ISSNs: 1471-0684

Abstract

Abstract: In a recent line of research, two familiar concepts from logic programming semantics (unfounded sets and splitting) were extrapolated to the case of epistemic logic programs. The property of epistemic splitting provides a natural and modular way to understand programs without epistemic cycles but, surprisingly, was only fulfilled by Gelfond's original semantics (G91), among the many proposals in the literature. On the other hand, G91 may suffer from a kind of self-supported, unfounded derivations when epistemic cycles come into play. Recently, the absence of these derivations was also formalised as a property of epistemic semantics called foundedness . Moreover, a first semantics proved to satisfy foundedness was also proposed, the so-called Founded Autoepistemic Equilibrium Logic (FAEEL). In this paper, we prove that FAEEL also satisfies the epistemic splitting property something that, together with foundedness, was not fulfilled by any other approach up to date. To prove this result, we provide an alternative characterisation of FAEEL as a combination of G91 with a simpler logic we called Founded Epistemic Equilibrium Logic (FEEL), which is somehow an extrapolation of the stable model semantics to the modal logic S5.