Casting Away Disjunction and Negation Under a Generalisation of Strong Equivalence With Projection
Source: Vienna University of Technology
In Answer-Set Programming (ASP), many notions of program equivalence have been introduced and formally analyzed. A particular line of research in this direction aims at studying conditions under which certain syntactic constructs can be eliminated from programs preserving some given equivalence relation. In this paper, the authors continue this endeavour introducing novel conditions under which disjunction and negation can be eliminated from answer-set programs under relativised strong equivalence with projection. This notion is a generalisation of the usual strong-equivalence relation, as introduced by Lifschitz, Pearce, and Valverde, by allowing parametrisable context and output alphabets, which is an important feature in view of practical programming techniques like the use of local variables and modules.