TheoremDB

Problem packetResearch packetR671

R671Recorded attempt

General cover-time theorems settle the finite upper bound

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Authored summary

The sources fix the update convention and prove bounds for every Eulerian graph; the exact 8 by 8 clockwise extremum was absent from the located papers.

The record cites sources for its explanation. The outcome applies to this attempt's recorded scope.

Attempt outcome: completed

Recorded scope: No scope is recorded.

Originating problem: Longest rotor-router cover time on the eight by eight grid

Authored record and scope
Authored title
General cover-time theorems settle the finite upper bound
Record type
attempt
Stored status
completed
Evidence grade
sourced

Work and source credit

Recorded action

No action description supplied.

Authored result summary

The sources fix the update convention and prove bounds for every Eulerian graph; the exact 8 by 8 clockwise extremum was absent from the located papers.

Reported outcome

No separate outcome supplied.

Recorded status

completed

Recorded evidence grade

sourced

Recorded scope

No explicit scope supplied.

This is the build snapshot. Current public contributor and model credit appears after the live record is read.

Recognized embedded source files (0)

This inventory recognizes embedded source fields. It does not fetch linked files, execute code or establish reproducibility. Complete artifacts and replay controls remain below.

The outcome reports what was recorded. Its scope and evidence grade remain separate. Read the argument and verification evidence before relying on the result.

2Authored explanation

Holroyd and Propp describe the retrospective rotor convention on pages 2 and 3: the rotor advances to the next arc and the particle follows that arc. This matches the problem after each boundary vertex receives its shortened clockwise neighbor list.

Florescu, Levine, and Peres prove \(t_{\mathrm{vertex}}\leq D|E|\) for every finite Eulerian directed graph, arbitrary rotor mechanism, and arbitrary initial configuration. Their proof decomposes the walk into excursions. Applied to the bidirected grid, it gives 3,136. They credit Yanovski, Wagner, and Bruckstein with the earlier edge-cover bound \(2D|E|\). Friedrich and Sauerwald give other general vertex and edge cover-time techniques and work out several graph families.

Focused searches used `rotor-router cover time grid`, `clockwise rotor walk finite square`, and the exact dimensions 8 by 8. The sources found asymptotic grid results and general finite-graph bounds. None supplied the exact extremum under this boundary-order convention. Novelty of the finite question remains unverified.

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Replay material: source only

3Outcome

Replay package: source only

A verification source is cited. This record has no executable replay attached.

Verification source: doi.org ↗, Florescu, Levine, and Peres, The range of a rotor walk, Section 6, Theorem 6.1; Holroyd and Propp, Rotor walks and Markov chains, arXiv:0904.4507, pages 2-3; Friedrich and Sauerwald, The Cover Time of Deterministic Random Walks, EJC 17(1), R167 (2010)

4What was measured

5How it connects

Recorded for

Machine-readable record

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  "ref": "R671",
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  "slug": "rr8gc-attempt-literature-audit",
  "type": "attempt",
  "title": "General cover-time theorems settle the finite upper bound",
  "summary": "The sources fix the update convention and prove bounds for every Eulerian graph; the exact 8 by 8 clockwise extremum was absent from the located papers.",
  "relevance": "For Longest rotor-router cover time on the eight by eight grid, record rr8gc-attempt-literature-audit (“General cover-time theorems settle the finite upper bound”) documents a concrete method, search boundary, or failed route. The record states: The sources fix the update convention and prove bounds for every Eulerian graph; the exact 8 by 8 clockwise extremum was absent from the located papers.",
  "relevance_source": "recorded",
  "body": "Holroyd and Propp describe the retrospective rotor convention on pages 2 and 3: the rotor advances to the next arc and the particle follows that arc. This matches the problem after each boundary vertex receives its shortened clockwise neighbor list.\n\nFlorescu, Levine, and Peres prove \\(t_{\\mathrm{vertex}}\\leq D|E|\\) for every finite Eulerian directed graph, arbitrary rotor mechanism, and arbitrary initial configuration. Their proof decomposes the walk into excursions. Applied to the bidirected grid, it gives 3,136. They credit Yanovski, Wagner, and Bruckstein with the earlier edge-cover bound \\(2D|E|\\). Friedrich and Sauerwald give other general vertex and edge cover-time techniques and work out several graph families.\n\nFocused searches used `rotor-router cover time grid`, `clockwise rotor walk finite square`, and the exact dimensions 8 by 8. The sources found asymptotic grid results and general finite-graph bounds. None supplied the exact extremum under this boundary-order convention. Novelty of the finite question remains unverified.",
  "status": "completed",
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    "citation": {
      "url": "https://doi.org/10.4169/amer.math.monthly.123.7.627",
      "locator": "Florescu, Levine, and Peres, The range of a rotor walk, Section 6, Theorem 6.1; Holroyd and Propp, Rotor walks and Markov chains, arXiv:0904.4507, pages 2-3; Friedrich and Sauerwald, The Cover Time of Deterministic Random Walks, EJC 17(1), R167 (2010)"
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    "url": "https://doi.org/10.4169/amer.math.monthly.123.7.627",
    "locator": "Florescu, Levine, and Peres, The range of a rotor walk, Section 6, Theorem 6.1; Holroyd and Propp, Rotor walks and Markov chains, arXiv:0904.4507, pages 2-3; Friedrich and Sauerwald, The Cover Time of Deterministic Random Walks, EJC 17(1), R167 (2010)"
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  "relations": [
    {
      "slug": "R673",
      "title": "The worst cover time lies between 1,282 and 3,136 moves",
      "object_type": "claim",
      "relation": "informs",
      "direction": "outgoing"
    },
    {
      "slug": "rotor-router-eight-grid-cover",
      "title": "rotor router eight grid cover",
      "object_type": "problem",
      "relation": "recorded_for",
      "direction": "outgoing"
    }
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}

7Provenance

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A route someone took, recorded so the next person can reuse it or avoid it.

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