New Techniques for Static Symmetry Breaking in Many-Sorted Finite Model Finding

Abstract

Symmetry in finite model finding problems of many-sorted first-order logic (MSFOL) can be exploited to reduce the number of interpretations considered during search, thereby improving solver performance for tools such as the Alloy Analyzer. We present a framework to soundly compose static symmetry breaking schemes for many-sorted finite model finding. Then, we introduce and prove the correctness of three static symmetry breaking schemes for MSFOL: 1) one for functions with distinct sorts in the domain and range; 2) one for functions where the range sort appears in the domain; and 3) one for predicates. We provide a novel presentation of sort inference in the context of symmetry breaking that yields a new mathematical link between sorts and symmetries. We empirically investigate how our symmetry breaking approaches affect solving performance.