@inproceedings{BergSJ:IJCAI2015, author = {Jeremias Berg and Paul Saikko and Matti J\"arvisalo}, title = {Improving the Effectiveness of {SAT}-Based Preprocessing for {MaxSAT}}, editor = {Qiang Yang and Michael Wooldridge}, booktitle = {Proceedings of the 24th International Joint Conference on Artificial Intelligence (IJCAI 2015)}, pages = {239--245}, year = {2015}, publisher = {AAAI Press}, } Abstract: Solvers for the Maximum satisfiability (MaxSAT) problem find an increasing number of applications today. We focus on improving MaxHS---one of the most successful recent MaxSAT algorithms---via SAT-based preprocessing. We show that employing SAT-based preprocessing via the so-called labelled CNF (LCNF) framework before calling MaxHS can in some cases greatly degrade performance of the solver. As a remedy, we propose a lifting of MaxHS that works directly on LCNFs, allowing for a tighter integration of SAT-based preprocessing and MaxHS. Our empirical results on standard crafted and industrial weighted partial MaxSAT Evaluation benchmarks show overall improvements over the original MaxHS algorithm both with and without SAT-based preprocessing.