,
Neil Thapen
Creative Commons Attribution 4.0 International license
It has become standard that, when a SAT solver decides that a CNF Γ is unsatisfiable, it produces a certificate of unsatisfiability in the form of a refutation of Γ in some proof system. The system typically used is DRAT, which is equivalent to extended resolution (ER) - for example, until this year DRAT refutations were required in the annual SAT competition. Recently [Bogaerts et al. 2023] introduced a new proof system, associated with the tool VeriPB, which is at least as strong as DRAT and is further able to handle certain symmetry-breaking techniques. We show that this system simulates the proof system G₁, which allows limited reasoning with QBFs and forms the first level above ER in a natural hierarchy of proof systems. This hierarchy is not known to be strict, but nevertheless this is evidence that the system of [Bogaerts et al. 2023] is plausibly strictly stronger than ER and DRAT. In the other direction, we show that symmetry-breaking for a single symmetry can be handled inside ER.
@InProceedings{kolodziejczyk_et_al:LIPIcs.SAT.2024.20,
author = {Ko{\l}odziejczyk, Leszek Aleksander and Thapen, Neil},
title = {{The Strength of the Dominance Rule}},
booktitle = {27th International Conference on Theory and Applications of Satisfiability Testing (SAT 2024)},
pages = {20:1--20:22},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-334-8},
ISSN = {1868-8969},
year = {2024},
volume = {305},
editor = {Chakraborty, Supratik and Jiang, Jie-Hong Roland},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.SAT.2024.20},
URN = {urn:nbn:de:0030-drops-205421},
doi = {10.4230/LIPIcs.SAT.2024.20},
annote = {Keywords: proof complexity, DRAT, symmetry breaking, dominance}
}