Compilation of aggregates in ASP: Preliminary results

Answer Set Programming (ASP) is a well-known problemsolving formalism in computational logic. Among the knowledge modeling constructs that make ASP effective in representing complex problems are aggregates. Aggregates operate on sets of literals and compute a single value (e.g., count, sum, etc.), thus, making the expression of constraints in ASP programs very concise. Traditionally, ASP systems are based on the ground & solve approach that suffers an intrinsic limitation known as grounding bottleneck: The grounding (variable elimination) can fill all the available memory and then the program cannot be evaluated. This happens also in programs that use aggregate functions. Recently, an alternative approach to evaluate ASP programs that avoids the grounding bottleneck has been proposed that is based on ASP program compilation. In this paper we present an extension of ASP program compilation that supports constraints containing the aggregate count. Preliminary experimental results demonstrate the viability of the approach.