Trimming Pseudo-Boolean Proofs

Berhan Oumer Adame, Bart Bogaerts, Benjamin Bogø, Simon Dold, Arthur Gontier, Wietze Koops, Ciaran McCreesh, Matthew McIlree, Jakob Nordström, Andy Oertel, Adrian Rebola-Pardo, and Mark Turnbull
Formal Methods in Computer-Aided Design 2026 (FMCAD 2026), 2026
To appear

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Abstract

Modern combinatorial solvers are very efficient but also highly complex and therefore error-prone. The most successful approach to ensure correctness — proof logging — is now the accepted standard for Boolean satisfiability (SAT) solving, where proof trimming is an additional crucial technique to reduce proof size and proof checking time. However, efficient proof logging has remained a challenge for richer combinatorial paradigms, and trimming has not been supported for the more complex proof logging systems used. In this work, we present a proof trimmer covering the full VeriPB proof format, bringing the advantages of trimming to a wide range of paradigms such as MaxSAT, pseudo-Boolean optimisation, subgraph solving, and constraint programming. Our experimental evaluation demonstrates that including proof trimming in the pipeline leads to overall reductions of proof size by a factor of~6.37 and of total proof checking time (including formally verified checking with CakePB) by a factor of 1.81.