Towards a Better Understanding of (Partial Weighted) MaxSAT Proof Systems

MaxSAT is a very popular language for discrete optimization with many domains of application. While there has been a lot of progress in MaxSAT solvers during the last decade, the theoretical analysis of MaxSAT inference has not followed the pace. Aiming at compensating that lack of balance, in this paper we do a proof complexity approach to MaxSAT resolution-based proof systems. First, we give some basic definitions on completeness and show that refutational completeness makes compleness redundant, as it happens in SAT. Then we take three inference rules such that adding them sequentially allows us to navigate from the weakest to the strongest resolution-based MaxSAT system available (i.e., from standalone MaxSAT resolution to the recently proposed ResE), each rule making the system stronger. Finally, we show that the strongest system captures the recently proposed concept of Circular Proof while being conceptually simpler, since weights, which are intrinsic in MaxSAT, naturally guarantee the flow condition required for the SAT case.