[#R1387] Current status and exact unresolved remainder
claim. OPEN as checked on 2026-08-01. Strongest checked neighboring result: Every n-vertex Barnette graph has a subhamiltonian cycle containing at least 5n/6 edges. The conjecture has been verified through 90 vertices and proved when every face has size at most 8. Exact unresolved remainder: Prove that every Barnette graph has a spanning cycle, or exhibit a cubic, 3-connected, bipartite planar graph without one. TheoremDB corpus searches for Barnette returned no duplicate target.
1Summary
The problem was checked as open on 2026-08-01.
The strongest neighboring result found in the cited sources is: Every n-vertex Barnette graph has a subhamiltonian cycle containing at least 5n/6 edges. The conjecture has been verified through 90 vertices and proved when every face has size at most 8.
Supported evidence. Replay readiness: source only.
2Evidence
A verification source is cited. This record has no executable replay attached.
Verification source: doi.org ↗, M. A. Bekos, M. Kaufmann, and M. Pfister, Approximating Barnette’s Conjecture, 33rd International Symposium on Graph Drawing and Network Visualization, LIPIcs 357, Article 6, pp. 6:1-6:7 (2025). Abstract, Introduction, Theorem 1, and Section 5
3Overview
The exact unresolved remainder is: Prove that every Barnette graph has a spanning cycle, or exhibit a cubic, 3-connected, bipartite planar graph without one. TheoremDB corpus searches for Barnette returned no duplicate target.
A complete resolution must meet the following acceptance conditions: - Prove that every finite simple cubic, 3-connected, bipartite planar graph has a Hamiltonian cycle. - Or give an explicit graph satisfying all four hypotheses, together with a rigorous certificate that it has no Hamiltonian cycle.
4What was measured
- As of
- 2026-08-01
- Exact open remainder
- Prove that every Barnette graph has a spanning cycle, or exhibit a cubic, 3-connected, bipartite planar graph without one. TheoremDB corpus searches for Barnette returned no duplicate target.
5How it connects
Informed by
- claim
Evidenced by
- attempt
Addressed by
- attempt
Recorded for
- problem
6Agent packet
A compact handoff with the evidence boundary, replay manifest, and relation pointers.
View structured packet
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"ref": "R1387",
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"slug": "barnette-conjecture-claim-status-20260801",
"type": "claim",
"title": "Current status and exact unresolved remainder",
"summary": "OPEN as checked on 2026-08-01. Strongest checked neighboring result: Every n-vertex Barnette graph has a subhamiltonian cycle containing at least 5n/6 edges. The conjecture has been verified through 90 vertices and proved when every face has size at most 8. Exact unresolved remainder: Prove that every Barnette graph has a spanning cycle, or exhibit a cubic, 3-connected, bipartite planar graph without one. TheoremDB corpus searches for Barnette returned no duplicate target.",
"relevance": "This is the dated publication status for the canonical target Barnette’s conjecture.",
"relevance_source": "recorded",
"body": "The problem was checked as open on 2026-08-01.\n\nThe strongest neighboring result found in the cited sources is: Every n-vertex Barnette graph has a subhamiltonian cycle containing at least 5n/6 edges. The conjecture has been verified through 90 vertices and proved when every face has size at most 8.\n\nThe exact unresolved remainder is: Prove that every Barnette graph has a spanning cycle, or exhibit a cubic, 3-connected, bipartite planar graph without one. TheoremDB corpus searches for Barnette returned no duplicate target.\n\nA complete resolution must meet the following acceptance conditions:\n- Prove that every finite simple cubic, 3-connected, bipartite planar graph has a Hamiltonian cycle.\n- Or give an explicit graph satisfying all four hypotheses, together with a rigorous certificate that it has no Hamiltonian cycle.",
"status": "reported",
"evidence_grade": "sourced",
"scope": null,
"reproduction": {
"schema": "theoremdb-reproduction-v1",
"readiness": "source_only",
"kind": "claim",
"citation": {
"url": "https://doi.org/10.4230/LIPIcs.GD.2025.6",
"locator": "M. A. Bekos, M. Kaufmann, and M. Pfister, Approximating Barnette’s Conjecture, 33rd International Symposium on Graph Drawing and Network Visualization, LIPIcs 357, Article 6, pp. 6:1-6:7 (2025). Abstract, Introduction, Theorem 1, and Section 5"
},
"missing": [
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"formal_statement": null,
"source": {
"url": "https://doi.org/10.4230/LIPIcs.GD.2025.6",
"locator": "M. A. Bekos, M. Kaufmann, and M. Pfister, Approximating Barnette’s Conjecture, 33rd International Symposium on Graph Drawing and Network Visualization, LIPIcs 357, Article 6, pp. 6:1-6:7 (2025). Abstract, Introduction, Theorem 1, and Section 5"
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"slug": "R1386",
"title": "Strongest checked neighboring result",
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"slug": "R1384",
"title": "Dated source and duplicate audit",
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{
"slug": "R1385",
"title": "Work at the unresolved boundary",
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}7Provenance
View source, identifiers, and projection details
- Project
- barnette-conjecture-release-300-source-review
- Locator
- M. A. Bekos, M. Kaufmann, and M. Pfister, Approximating Barnette’s Conjecture, 33rd International Symposium on Graph Drawing and Network Visualization, LIPIcs 357, Article 6, pp. 6:1-6:7 (2025). Abstract, Introduction, Theorem 1, and Section 5
- License
- CC0-1.0
- Contributors
- TheoremDB maintainers
- Source
- doi.org ↗
- Public record
- R1387
- Stable alias
- barnette-conjecture-claim-status-20260801
- Projection
- Reproduction fields are derived from the immutable record.
A statement this project treats as settled at the recorded evidence grade, with the work that backs it.