Study: Symmetry breaking for ASP

TL;DR

This paper addresses the challenge of symmetry in combinatorial configuration problems, proposing methods to identify and break symmetries to improve solver efficiency and optimize search processes.

Contribution

It introduces novel symmetry-breaking techniques tailored for Answer Set Programming (ASP) to enhance problem-solving efficiency.

Findings

Symmetry breaking reduces search space and improves solver performance.

The proposed methods effectively identify symmetric solutions in ASP.

Experimental results show significant speed-ups in solving configuration problems.

Abstract

In their nature configuration problems are combinatorial (optimization) problems. In order to find a configuration a solver has to instantiate a number of components of a some type and each of these components can be used in a relation defined for a type. Therefore, many solutions of a configuration problem have symmetric ones which can be obtained by replacing some component of a solution by another one of the same type. These symmetric solutions decrease performance of optimization algorithms because of two reasons: a) they satisfy all requirements and cannot be pruned out from the search space; and b) existence of symmetric optimal solutions does not allow to prove the optimum in a feasible time.