End-to-End Certified Graph Colouring
Paper in proceeding, 2026
Applied combinatorial optimization has witnessed a revolution in performance since the turn of the millennium, but the complexity of modern solvers is making bugs an ever more serious concern. The most promising remedy is to make solvers certifying, so that they use proof logging to generate machine-verifiable proofs of correctness. We present the first example of state-of-the-art certified graph colouring by equipping the solver ZykovColor with VeriPB proof logging. Combined with the formally verified CakePB checker, this provides end-to-end formally certified results. An experimental evaluation shows excellent results with only moderate overhead for proof logging and checking.
certifying algorithms
proof logging
graph colouring
Author
Simon Dold
University of Basel
Wietze Koops
University of Copenhagen
Lund University
Jakob Nordström
Lund University
University of Copenhagen
Yong Kiam Tan
Nanyang Technological University
Agency for Science, Technology and Research (A*STAR)
George Katsirelos
University Paris-Saclay
Paul Sabatier University
Magnus Myreen
Chalmers, Computer Science and Engineering (Chalmers), Formal methods
University of Gothenburg
Andy Oertel
University of Copenhagen
Lund University
Leibniz International Proceedings in Informatics, LIPIcs
18688969 (ISSN)
Vol. 379 219783959774321 (ISBN)
32nd International Conference on Principles and Practice of Constraint Programming, CP 2026
Lisbon, Portugal,
Lisbon, Portugal,
The next 700 verified compilers
Swedish Research Council (VR) (2021-05165), 2022-01-01 -- 2025-12-31.
Subject Categories (SSIF 2025)
Computer Sciences
DOI
10.4230/LIPIcs.CP.2026.21