TheoremDB
R81claimStatus: establishedEvidence: ReproducedReplay: source onlyexhaustive over its scope

[#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.

View evidenceOpen source ↗

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

Evidence package: source only

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

min5max7

Lower bound obstruction

largest first reply class400transcripts available in three more queries343

Upper strategy

kindadaptive deterministic greedy treemaximum depth7internal nodes484singleton leaves924total nodes1,408

4How it connects

Verifies (incoming)

Informed by

Targets (incoming)

Recorded for

5Agent packet

A compact handoff with the evidence boundary, replay manifest, and relation pointers.

View structured packet
json
{
  "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
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.

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