A tool for advanced correspondence checking in answer-set programming : Preliminary experimental results

In recent work, a general framework for specifying program correspondences under the answer-set semantics has been defined. The framework allows to define different notions of equivalence, including the well-known notions of strong and uniform equivalence, as well as refined equivalence notions based on the projection of answer sets, where not all parts of an answer set are of relevance (like, e.g., removal of auxiliary letters). In the general case, deciding the correspondence of two programs lies on the fourth level of the polynomial hierarchy and therefore this task can (presumably) not be efficiently reduced to answer-set programming. In this paper, we give an overview about an implementation to compute program correspondences in this general framework. The system, called eqcheck, relies on linear-time constructible reductions to quantified propositional logic using extant solvers for the latter language as back-end inference engines. We provide some preliminary performance evaluation, which shed light on some crucial design issues.