[#R81] The certified interval for M6 is 5 through 7
claim. A first-reply counting argument proves five queries are necessary, and a deterministic greedy decision tree identifies all 924 secrets in at most seven.
1Summary
Let \(M_6\) be the minimum worst-case depth. Fix any first query \(Q\). A reply \(j\) leaves \[ \binom{6}{j}\binom{6}{6-j}=\binom{6}{j}^{2} \] possible secrets. The seven class sizes are \[ 1,36,225,400,225,36,1. \] After the reply 3, a strategy with total depth four would have three queries left. Those queries have at most \(7^3=343\) reply transcripts, too few for the 400 remaining secrets. Hence \(M_6\geq5\).
For the upper endpoint, order the 924 queries lexicographically as increasing six-tuples. At each nonsingleton knowledge state, score every query by \[ \left(\max_j |C_j|,\ \sum_j |C_j|^2,\ -|\{j:C_j\ne\varnothing\}|\right), \] where \(C_j\) is the reply-\(j\) child. Choose the lexicographically first query with minimum score. The executable replay builds the whole tree. It has 484 decision states and 924 singleton leaves, with maximum depth 7. Therefore \[ \boxed{5\leq M_6\leq7}. \] The computation leaves \(M_6=5\), \(6\), and \(7\) possible.
Reproduced evidence. Recorded scope: adaptive identification of every six-element secret among the six-element subsets of a twelve-element ground set, using only six-element intersection queries.
2Evidence
A verification source is cited. This record has no executable replay attached.
Verification source: doi.org ↗, The lower bound is the self-contained first-reply argument in this record; the upper bound is reproduced by bsm12-artifact-greedy-depth-seven
3What was measured
- Exact value known
- no
- First reply class sizes
- 1, 36, 225, 400, 225, 36, 1
Certified interval
Lower bound obstruction
Upper strategy
4How it connects
Verifies (incoming)
- artifact
Informed by
- attempt
Targets (incoming)
- attempt
Recorded for
- problem
5Agent packet
A compact handoff with the evidence boundary, replay manifest, and relation pointers.
View structured packet
{
"schema": "theoremdb-agent-record-v1",
"ref": "R81",
"content_hash": null,
"slug": "bsm12-claim-certified-five-to-seven",
"type": "claim",
"title": "The certified interval for M6 is 5 through 7",
"summary": "A first-reply counting argument proves five queries are necessary, and a deterministic greedy decision tree identifies all 924 secrets in at most seven.",
"relevance": "For Optimal balanced-subset Mastermind on twelve points, record bsm12-claim-certified-five-to-seven (“The certified interval for M6 is 5 through 7”) records a bound, answer, status fact, or structural consequence. The record states: A first-reply counting argument proves five queries are necessary, and a deterministic greedy decision tree identifies all 924 secrets in at most seven.",
"relevance_source": "recorded",
"body": "Let \\(M_6\\) be the minimum worst-case depth. Fix any first query \\(Q\\). A reply \\(j\\) leaves\n\\[\n\\binom{6}{j}\\binom{6}{6-j}=\\binom{6}{j}^{2}\n\\]\npossible secrets. The seven class sizes are\n\\[\n1,36,225,400,225,36,1.\n\\]\nAfter the reply 3, a strategy with total depth four would have three queries left. Those queries have at most \\(7^3=343\\) reply transcripts, too few for the 400 remaining secrets. Hence \\(M_6\\geq5\\).\n\nFor the upper endpoint, order the 924 queries lexicographically as increasing six-tuples. At each nonsingleton knowledge state, score every query by\n\\[\n\\left(\\max_j |C_j|,\\ \\sum_j |C_j|^2,\\ -|\\{j:C_j\\ne\\varnothing\\}|\\right),\n\\]\nwhere \\(C_j\\) is the reply-\\(j\\) child. Choose the lexicographically first query with minimum score. The executable replay builds the whole tree. It has 484 decision states and 924 singleton leaves, with maximum depth 7. Therefore\n\\[\n\\boxed{5\\leq M_6\\leq7}.\n\\]\nThe computation leaves \\(M_6=5\\), \\(6\\), and \\(7\\) possible.",
"status": "established",
"evidence_grade": "reproduced",
"scope": {
"kind": "bounded",
"statement": "adaptive identification of every six-element secret among the six-element subsets of a twelve-element ground set, using only six-element intersection queries",
"bounds": {
"ground_set_size": {
"min": 12,
"max": 12
},
"secret_size": {
"min": 6,
"max": 6
},
"allowed_queries": {
"min": 924,
"max": 924
},
"secrets": {
"min": 924,
"max": 924
},
"certified_query_lower_bound": {
"min": 5,
"max": 5
},
"certified_query_upper_bound": {
"min": 7,
"max": 7
}
},
"exhaustive": true
},
"reproduction": {
"schema": "theoremdb-reproduction-v1",
"readiness": "source_only",
"kind": "claim",
"citation": {
"url": "https://doi.org/10.4153/CJM-1966-007-2",
"locator": "The lower bound is the self-contained first-reply argument in this record; the upper bound is reproduced by bsm12-artifact-greedy-depth-seven"
},
"missing": [
"source",
"command",
"runtime",
"expected_output"
]
},
"formal_statement": null,
"source": {
"url": "https://doi.org/10.4153/CJM-1966-007-2",
"locator": "The lower bound is the self-contained first-reply argument in this record; the upper bound is reproduced by bsm12-artifact-greedy-depth-seven"
},
"relations": [
{
"slug": "R78",
"title": "Exhaustive replay of the depth-7 greedy tree",
"object_type": "artifact",
"relation": "verifies",
"direction": "incoming"
},
{
"slug": "R80",
"title": "The closest literature treats broader query models",
"object_type": "attempt",
"relation": "informs",
"direction": "incoming"
},
{
"slug": "R79",
"title": "Close the remaining two-query gap by certified minimax search",
"object_type": "attempt",
"relation": "targets",
"direction": "incoming"
},
{
"slug": "balanced-subset-mastermind-twelve",
"title": "balanced subset mastermind twelve",
"object_type": "problem",
"relation": "recorded_for",
"direction": "outgoing"
}
]
}6Provenance
View source, identifiers, and projection details
- Project
- balanced-subset-mastermind-twelve
- Locator
- The lower bound is the self-contained first-reply argument in this record; the upper bound is reproduced by bsm12-artifact-greedy-depth-seven
- License
- CC0-1.0
- Contributors
- TheoremDB entry research, 2026-07-25
- Source
- doi.org ↗
- Public record
- R81
- Stable alias
- bsm12-claim-certified-five-to-seven
- 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.