Aggregates In Answer Set Optimization

Answer set optimization (ASO) is a flexible framework for qualitative optimization in answer set programming (ASP). The approach uses a generating program to construct the space of problem solutions, and a preference program to assess the quality of solutions. In this short paper we generalize the approach by introducing aggregates in preference programs. This allows the user to express preferences which are based on minimization or maximization of some numerical criteria. We introduce the new language of preference programs, define its semantics and give an example illustrating its use.