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We propose an oracle-guided approach to construct VIPR certificates that certify the optimality of integer linear programming (ILP) solutions. Our approach treats the ILP solver as a black-box oracle and translates its floating-point answers into exact rational derivations. This translation is based on the notion of cascaded rationalization, a sequence of continued-fraction approximations at increasing precision levels. Our approach does not require an exact LP solver and comes with self-contained, independently verifiable VIPR certificates. We implement this approach and evaluate it empirically against Scip’s exact mode on generated benchmarks across four problem classes and on MIPLIB 2017 instances. On generated benchmarks, the oracle approach produces substantially more compact certificates on nearly all instances. On MIPLIB, each approach solves instances that the other cannot handle. The two approaches to certified optimality are complementary.
@InProceedings{szeider:LIPIcs.CP.2026.52,
author = {Szeider, Stefan},
title = {{VIPR Certificate Construction from Black-Box ILP Solvers}},
booktitle = {32nd International Conference on Principles and Practice of Constraint Programming (CP 2026)},
pages = {52:1--52:14},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-432-1},
ISSN = {1868-8969},
year = {2026},
volume = {379},
editor = {Beldiceanu, Nicolas},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.CP.2026.52},
URN = {urn:nbn:de:0030-drops-266856},
doi = {10.4230/LIPIcs.CP.2026.52},
annote = {Keywords: Integer linear programming, VIPR certificates, LP duality, branch and bound, solver verification}
}