Problem packetResearch packetR346
Trees with no alpha-labeling: the count doubles, the share peaks and falls
Link to a section
The recorded result has been reproduced within its stated scope.
Recorded status: reproduced
Recorded scope: trees on 7 to 15 vertices
Complete recorded scope and conditions
{
"kind": "bounded",
"statement": "trees on 7 to 15 vertices",
"bounds": {
"n": {
"max": 15,
"min": 7
}
},
"exhaustive": true
}Originating problem: Graceful tree conjecture
Authored record and scope
- Authored title
- Trees with no alpha-labeling: the count doubles, the share peaks and falls
- Record type
- claim
- Stored status
- reproduced
- Evidence grade
- reproduced
- Recorded scope data
- { "kind": "bounded", "statement": "trees on 7 to 15 vertices", "bounds": { "n": { "max": 15, "min": 7 } }, "exhaustive": true }
2Authored explanation
Counts of trees on \(n\) vertices with no alpha-labeling, from exhaustive search: n=7: 1, n=8: 2, n=9: 5, n=10: 11, n=11: 22, n=12: 44, n=13: 82, n=14: 147, n=15: 254. As a share of all trees of that size: n=7: 9.1%, n=8: 8.7%, n=9: 10.6%, n=10: 10.4%, n=11: 9.4%, n=12: 8.0%, n=13: 6.3%, n=14: 4.7%, n=15: 3.3%.
The two series move in opposite directions, and the distinction decides what an alpha-based argument can claim. The absolute count grows by about 1.8 per vertex, so the set of trees such an argument cannot reach keeps getting larger. The share peaks at 10.6% around n=9 and then falls, reaching 3.3% by n=15, so those trees are becoming rarer among all trees of their size.
Whether the share continues down is open, and the answer is what would turn an alpha-based method into an asymptotic result. The measured range is short.
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Replay material: source only
3Evidence
A verification source is cited. This record has no executable replay attached.
Verification source: arxiv.org ↗, research/graceful-trees/checks.py --max-n 15
4What was measured
Alpha free by n
5How it connects
Constrains
- attempt
Informs
- problem
Evidenced by
- artifact
Recorded for
- problem
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Cite the original sources separately.
Machine-readable record
Copy the structured record when continuing this work with an agent.
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"title": "Trees with no alpha-labeling: the count doubles, the share peaks and falls",
"summary": "Counted exhaustively: n=7: 1, n=8: 2, n=9: 5, n=10: 11, n=11: 22, n=12: 44, n=13: 82, n=14: 147, n=15: 254. The count grows by about 1.8 per vertex, while the share of all trees peaks at 10.6% at n=9 and falls to 3.3% at n=15.",
"relevance": "For Graceful tree conjecture, record gtc-claim-alpha-growth (“Trees with no alpha-labeling: the count doubles, the share peaks and falls”) records a bound, answer, status fact, or structural consequence. The record states: Counted exhaustively: n=7: 1, n=8: 2, n=9: 5, n=10: 11, n=11: 22, n=12: 44, n=13: 82, n=14: 147, n=15: 254.",
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}7Provenance
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