TheoremDB

Problem packetResearch packetR697

R697Executable evidence

Exact subtract-a-cube sweep through 200,000

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Link to a section

Authored summary

Exact dynamic programming finds 21,912 positive P-positions through 200,000 and a density of 0.10956 at the endpoint.

Executable material is recorded. Successful replay is a separate check.

Recorded status: available

Recorded scope: every starting heap size from 0 through 200000

Complete recorded scope and conditions
{
  "kind": "bounded",
  "statement": "every starting heap size from 0 through 200000",
  "bounds": {
    "n": {
      "min": 0,
      "max": 200000
    }
  },
  "exhaustive": true
}

Originating problem: Density of losing positions in the subtract-a-cube game

Source files are not attached to this record. Check the recorded source for access.

Authored record and scope
Authored title
Exact subtract-a-cube sweep through 200,000
Record type
artifact
Stored status
available
Evidence grade
executable
Recorded scope data
{ "kind": "bounded", "statement": "every starting heap size from 0 through 200000", "bounds": { "n": { "min": 0, "max": 200000 } }, "exhaustive": true }

2Authored explanation

The program computes every Sprague-Grundy value in increasing heap order using all positive cubes at most the current heap size. The P-position counts are 1,684 through 10,000, 6,815 through 50,000, 13,002 through 100,000, and 21,912 through 200,000. The first positive P-positions are 2, 4, 6, 9, 11, 13, 15, 18, 20, 22, 24, and 34. The maximum Grundy value in the range is 20, first reached at 167,122.

The sweep is finite evidence for the rate of decay. The density-zero claim above follows from the cited theorem.

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Replay material: partial

3Reproduce

Replay package: partial

Part of the replay path is recorded. Check the missing fields before comparing a new run.

Verification source: github.com ↗, research/candidate-screening/multi2.py, deeper subtraction-game sweep; independently rerun on 2026-07-24

Missing for a complete replay: command, runtime, expected output.

Recorded artifact fields

4What it produced

P position counts

100001,684500006,81510000013,00220000021,912

5How it connects

Recorded for

Machine-readable record

Copy the structured record when continuing this work with an agent.

json
{
  "schema": "theoremdb-agent-record-v1",
  "ref": "R697",
  "content_hash": null,
  "slug": "sac-artifact-sweep-200000",
  "type": "artifact",
  "title": "Exact subtract-a-cube sweep through 200,000",
  "summary": "Exact dynamic programming finds 21,912 positive P-positions through 200,000 and a density of 0.10956 at the endpoint.",
  "relevance": "This supplies a computation, dataset, or executable check used to assess the target problem.",
  "relevance_source": "derived",
  "body": "The program computes every Sprague-Grundy value in increasing heap order using all positive cubes at most the current heap size. The P-position counts are 1,684 through 10,000, 6,815 through 50,000, 13,002 through 100,000, and 21,912 through 200,000. The first positive P-positions are 2, 4, 6, 9, 11, 13, 15, 18, 20, 22, 24, and 34. The maximum Grundy value in the range is 20, first reached at 167,122.\n\nThe sweep is finite evidence for the rate of decay. The density-zero claim above follows from the cited theorem.",
  "status": "available",
  "evidence_grade": "executable",
  "scope": {
    "kind": "bounded",
    "statement": "every starting heap size from 0 through 200000",
    "bounds": {
      "n": {
        "min": 0,
        "max": 200000
      }
    },
    "exhaustive": true
  },
  "reproduction": {
    "schema": "theoremdb-reproduction-v1",
    "readiness": "partial",
    "kind": "python_computation",
    "source": "research/candidate-screening/multi2.py",
    "citation": {
      "url": "https://github.com/philipfweiss/theoremdb/blob/main/research/candidate-screening/multi2.py",
      "locator": "research/candidate-screening/multi2.py, deeper subtraction-game sweep; independently rerun on 2026-07-24"
    },
    "missing": [
      "command",
      "runtime",
      "expected_output"
    ]
  },
  "formal_statement": null,
  "source": {
    "url": "https://github.com/philipfweiss/theoremdb/blob/main/research/candidate-screening/multi2.py",
    "locator": "research/candidate-screening/multi2.py, deeper subtraction-game sweep; independently rerun on 2026-07-24"
  },
  "models": [],
  "continuation": null,
  "relations": [
    {
      "slug": "R699",
      "title": "Subtract-a-cube losing positions have density zero",
      "object_type": "claim",
      "relation": "tests",
      "direction": "outgoing"
    },
    {
      "slug": "R698",
      "title": "Determine the growth order of the greedy cube-difference-free set",
      "object_type": "attempt",
      "relation": "uses",
      "direction": "incoming"
    },
    {
      "slug": "subtract-a-cube-density",
      "title": "subtract a cube density",
      "object_type": "problem",
      "relation": "recorded_for",
      "direction": "outgoing"
    }
  ]
}

7Provenance

View source, identifiers, and projection details

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