Abstraction for Non-ground Answer Set Programs.

We address the issue of abstraction, a widely used notion to simplify problems, in the context of Answer Set Programming (ASP), which is a highly expressive formalism and a convenient tool for declarative problem solving. We introduce a method to automatically abstract non-ground ASP programs given an abstraction over the domain, which ensures that each original answer set is mapped to some abstract answer set. We discuss abstraction possibilities on several examples and show the use of abstraction to gain insight into problem instances, e.g., domain details irrelevant for problem solving; this makes abstraction attractive for getting to the essence of the problem. We also provide a tool implementing automatic abstraction from an input program.