What was already known
The original rounding theorem permits additive congestion; preserving cost simultaneously was a stronger conjecture.
What changed and why it matters
Advances the stated target relative to the recorded baseline.
The AI contribution
The original announcement credits model-assisted discovery. The AFP authors explicitly disclose AI-assisted proof engineering of the finite instance.
Limitations
The formal model and its correspondence to the cost-congestion statement matter. AIProofWatch has not rebuilt Isabelle. Discovery attribution to Rybin’s model-assisted workflow is distinct from the later proof engineering.
Verification evidence
Evidence labels show what supports the claim. Importance rates its impact if correct.
Author claim
The AFP abstract states the finite cost-congestion counterexample.
Accessible artifact / proof
Isabelle session and proof documents are available.
Formal checking
AFP reports Isabelle checking; not rebuilt by AIProofWatch.
Checker: Ramos, Hulak and de Queiroz / Archive of Formal Proofs
Scope: The seven-vertex finite path-flow instance: fractional cost 58 versus unsplittable cost at least 60 with additive congestion 15.
Basis: Reported by the linked checker
Checking a formal statement does not establish that it matches the original problem.
Correction and publication history
Full source review, 11 October 2026. Historical addition; subscriber alerts disabled.
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