Abstract Cores

in Implicit Hitting Set-based MaxSAT

During my visit to Toronto in 2019. We worked on extending the implicit hitting set (IHS) algorithm for MaxSAT with abstract cores, which can be seen as a hybridization between core-guided and hitting set-based algorithms, as well as symmetry breaking. The work was recognized with a paper award at the 2020 SAT conferece, the flagship conference of the research field of Boolean satisfiability.

We show how adding abstract cores into the MaxSAT solver MaxHS significantly improves its performance. The solver took top positions in the 2020 and 2021 MaxSAT Evaluations. More recently, we have shown how abstract cores can be used as a basis for a framework that unifies most of the existing SAT-based MaxSAT algorithms.

MaxHS is available in open source here, as long as you have a MIP solver to use for the hitting set computations.