Alternative Characterizations for Program Equivalence under Answer-Set Semantics: Preliminary Report

The 30th USA and Japanese National Research Aquaculture Panel Symposium

社会科学（总论）;生物科学

Martin Gebser ; Torsten Schaub ; Hans Tompits ; Stefan Woltran

Others  :  http://CEUR-WS.org/Vol-265/CENT2007-paper5.pdf
PID  :  1024

来源: CEUR

【 摘 要 】

Logic programs under answer-set semantics constitute an important tool for declarative problem solving. In recent years, two research issues received growing attention. On the one hand, concepts like loops and elementary sets have been proposed in order to extend Clark’s completion for computing answer sets of logic programs by means of propositional logic. On the other hand, different concepts of program equivalence, like strong or uniform equivalence, have been studied in the context of program optimization and modular programming. In this paper, we bring these two lines of research together and provide alternative characterizations for different conceptions of equivalence in terms of unfounded sets, along with the related concepts of loops and elementary sets. Our results yield new insights into the model theory of equivalence checking. We further ex- ploit these characterizations to develop novel encodings of program equivalence in terms of propositional logic.