An Extension of the System cc⊤ for Testing Relativised Uniform Equivalence under Answer-Set Projection

The system cc⊤ is a tool for testing correspondence between nonmonotonic logic programs under the answer-set semantics with respect to different refined notions of program correspondence. The basic architecture of cc⊤ is to reduce a given correspondence problem into the satisfiability problem for quantified propositional logic and to employ off-the-shelf solvers for the latter language as backend inference engines. In a previous incarnation of cc⊤, the system was designed to test correspondence between logic programs based on relativised strong equivalence under answer-set projection. Such a setting generalises the usual notion of strong equivalence by taking the alphabet of the context programs as well as the projection of the compared answer sets to a set of designated output atoms into account. In this paper, we describe an extension of cc⊤ for testing similarly parameterised correspondence problems but generalising uniform equivalence, which have recently been introduced in previous work. Besides reviewing the formal underpinnings of the new component of cc⊤, we discuss an alternative encoding as well as optimisations for special problem classes. Furthermore, we give a prelimiThe authors of this work were partially supported by the Austrian Science Fund (FWF) under grant P18019; the second author was also supported by the Austrian Federal Ministry of Transport, Innovation, and Technology (BMVIT) and the Austrian Research Promotion Agency (FFG) under grant FIT-IT-810806. nary performance evaluation of the new component.