Home Problems Cost-preserving unsplittable flow Research history Selected research history · publication v1
Cost-preserving unsplittable flow Follow the ideas, results and limitations over time. This is a selected history, not a complete literature survey or a measure of how close the problem is to being solved.
Current state & remaining question → Viewing the timeline from pinned publication v1.
5 selected milestones · Source coverage checked 2026-10-13 · Historical annotation and mathematical review remain separate.
1999 publication
Related result
The original congestion theorem Dinitz, Garg and Goemans establish additive congestion bounded by the largest demand.
Scope & review: The folklore cost strengthening is a separate assertion, later stated as Conjecture 1.3 in the 2023 paper.
Statements & sources Historical annotation review: pending. The date refers to the publication, with the precision supported by the source.
Aug 4, 2023 preprint
Related result
A planar theorem preserves cost with a larger allowance Traub, Vargas Koch and Zenklusen prove the cost guarantee with two-sided deviation at most twice the largest demand.
Scope & review: The larger allowance is essential to distinguishing this theorem from the refuted question.
Statements & sources Historical annotation review: pending. The date refers to the preprint, with the precision supported by the source.
Jul 22, 2026 announcement
Related result
Rybin announces the finite counterexample The verification projects attribute the discovery to Dmitry Rybin’s GPT-5.6 Pro session.
Scope & review: The original discovery and subsequent formal checks are separate contributions.
Statements & sources Historical annotation review: pending. The date refers to the announcement, with the precision supported by the source.
Jul 22, 2026 formalization
Formalization
The AFP records an Isabelle verification Ramos, Hulak and de Queiroz supply the generic flow model and exhaustive finite argument.
Scope & review: The AFP entry date is distinct from the generated document’s August revision date.
Statements & sources Historical annotation review: pending. The date refers to the formalization, with the precision supported by the source.
Aug 1, 2026 formalization
Formalization
A pinned independent Lean verification Jason Hickey’s project checks the exact optimum and the literature-faithful conjecture refutation.
Scope & review: This is a source-reported verification, not an OpenMath build.
Statements & sources Historical annotation review: pending. The date refers to the formalization, with the precision supported by the source.
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