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Two flavors of DRAT

17 pagesPublished: March 15, 2019


DRAT proofs have become the de facto standard for certifying SAT solvers’ results. State-of-the-art DRAT checkers are able to efficiently establish the unsatisfiability of a formula. However, DRAT checking requires unit propagation, and so it is computationally non-trivial. Due to design decisions in the development of early DRAT checkers, the class of proofs accepted by state-of-the-art DRAT checkers differs from the class of proofs accepted by the original definition. In this paper, we formalize the operational definition of DRAT proofs, and discuss practical implications of this difference for generating as well as checking DRAT proofs. We also show that these theoretical differences have the potential to affect whether some proofs generated in practice by SAT solvers are correct or not.

Keyphrases: DRAT proofs, proof checking, Unsatisfiability proof generation

In: Daniel Le Berre and Matti Järvisalo (editors). Proceedings of Pragmatics of SAT 2015 and 2018, vol 59, pages 94--110

BibTeX entry
  author    = {Adrian Rebola Pardo and Armin Biere},
  title     = {Two flavors of DRAT},
  booktitle = {Proceedings of Pragmatics of SAT 2015 and 2018},
  editor    = {Daniel Le Berre and Matti J\textbackslash{}"arvisalo},
  series    = {EPiC Series in Computing},
  volume    = {59},
  pages     = {94--110},
  year      = {2019},
  publisher = {EasyChair},
  bibsource = {EasyChair,},
  issn      = {2398-7340},
  url       = {},
  doi       = {10.29007/lt8r}}
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