Disproved
Counterexample reported with checked SAT certificates ↗
Universal Petersen coloring assertion; minimum counterexample order is not determined.
Source dated Aug 8, 2026 · Observed Oct 14, 2026
Conjecture · version 1
Every finite loopless bridgeless cubic graph has a proper edge-coloring with at most five colors in which the union of the palettes at the endpoints of every edge has either three or five colors.
Disproved
Universal Petersen coloring assertion; minimum counterexample order is not determined.
Source dated Aug 8, 2026 · Observed Oct 14, 2026
In this problem · publication v7 · Selected context
Equivalent formulation · Disproved
Jaeger’s theorem gives equivalent existence conditions for each loopless cubic graph.
The positive universal assertions are both refuted by the reported witness; equivalence remains a valid theorem.
Disproved · version 1
Every finite loopless bridgeless cubic graph admits an edge map to the Petersen graph that maps each incident edge-star bijectively onto a target vertex’s edge-star.
Scope: Parallel edges are allowed; the simple connected witness already lies in this class.
Disproved · version 1
Every finite loopless bridgeless cubic graph has a proper edge-coloring with at most five colors in which the union of the palettes at the endpoints of every edge has either three or five colors.
Scope: A poor edge has three colors across its endpoint stars; a rich edge has five. Four is forbidden.
Relationship statement · Proved · version 1
For each finite loopless cubic multigraph, the existence of a Petersen coloring is equivalent to the existence of a normal five-edge-coloring.
Scope: The paper gives an explicit bijection using P = KG(5,2). Bridgelessness is not needed for this equivalence.
Relationship not independently reviewed.
Connection in Petersen coloring conjecture →Relationship not independently reviewed. This concerns its use in this problem.
The edge-star formulation is equivalent to the existence of a normal five-edge-coloring. The original conjecture concerns every bridgeless cubic graph.
paraphrase · Linked proof prose is not republished. Any copied graph data is CC0, as specified by its archive.
The main graph has 112 vertices, 168 edges, girth five and edge- and vertex-connectivity three. Section 3 specifies its recursive construction.
paraphrase · Linked proof prose is not republished. Any copied graph data is CC0, as specified by its archive.
Bryce Putman · Preprint · Publication date Aug 8, 2026
Source-reported results and external checks are separate from independent OpenMath assessment.
Source revision: v1. Observed Oct 14, 2026.
Putman reports extensive OpenAI-model assistance in discovery, search, verification and preparation; he reviewed the final claims and artifacts and accepts responsibility.
Statement versions and problem publication versions are separate. A new publication can update context or sources while retaining the same statement.
Assessments retained in these publication records. Earlier statement versions retain their own source histories.
Disproved
Universal Petersen coloring assertion; minimum counterexample order is not determined.
Source dated Aug 8, 2026 · Observed Oct 14, 2026 · Source passage →