Title
Hard QBFs for Merge Resolution
Abstract
We prove the first proof size lower bounds for the proof system Merge Resolution (MRes [Olaf Beyersdorff et al., 2020]), a refutational proof system for prenex quantified Boolean formulas (QBF) with a CNF matrix. Unlike most QBF resolution systems in the literature, proofs in MRes consist of resolution steps together with information on countermodels, which are syntactically stored in the proofs as merge maps. As demonstrated in [Olaf Beyersdorff et al., 2020], this makes MRes quite powerful: it has strategy extraction by design and allows short proofs for formulas which are hard for classical QBF resolution systems. Here we show the first exponential lower bounds for MRes, thereby uncovering limitations of MRes. Technically, the results are either transferred from bounds from circuit complexity (for restricted versions of MRes) or directly obtained by combinatorial arguments (for full MRes). Our results imply that the MRes approach is largely orthogonal to other QBF resolution models such as the QCDCL resolution systems QRes and QURes and the expansion systems $\forall$Exp+Res and IR.
Year
DOI
Venue
2020
10.4230/LIPIcs.FSTTCS.2020.12
FSTTCS
DocType
Volume
Citations 
Conference
27
0
PageRank 
References 
Authors
0.34
0
5
Name
Order
Citations
PageRank
Olaf Beyersdorff122330.33
Joshua Blinkhorn236.16
Meena Mahajan368856.90
Tomás Peitl464.82
Gaurav Sood500.34