TheoremDB

Problem packetWorkR220

R220claimStatus: establishedEvidence: ReproducedReplay: source onlyexhaustive over its scope

[#R220] The minimum lies between 15 and 18

claim. Pair counting gives the lower endpoint, while a new 18-element exponent set covers every class modulo 100.

View evidenceOpen source ↗

1Summary

Write every nonzero field element as \(2^t\). The congruences \[ 2^{20}=95,\qquad 2^{50}=100,\qquad 2^{100}=1\pmod {101} \] show that 2 has order 100. A set of field elements is therefore a distinct-product basis exactly when its discrete logarithms form a strict sum cover of \(\mathbf Z/100\mathbf Z\).

If the basis has \(k\) elements, its distinct unordered pairs produce at most \(\binom{k}{2}\) products. Covering all 100 nonzero elements requires \(\binom{k}{2}\geq100\), hence \(k\geq15\).

Reproduced evidence. Recorded scope: all distinct-product bases in the multiplicative group of F_101, together with the displayed 18-element witness.

2Evidence

Replay package: source only

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

Verification source: cs.uwaterloo.ca ↗, Elementary counting and the exact replay in dpb101-artifact-eighteen-point-cover-check

3Overview

For the upper bound, take the exponent set \[ B=\{0,1,4,10,16,18,23,29,36,50,57,63,68,70,76,82,85,86\}. \] The 153 sums \(b+b'\pmod {100}\), with \(b,b'\in B\) and \(b\ne b'\), contain every residue class. Equivalently, the field set \[ \{1,2,6,14,16,23,33,49,52,53,59,62,74,78,81,88,90,100\} \] has all 100 nonzero field elements among its products of distinct members. Thus the unknown minimum \(m\) satisfies \[ 15\leq m\leq18. \] This improves the candidate record's certified upper bound of 19. It leaves sizes 15, 16, and 17 unresolved.

4What was measured

Lower bound
15
Upper bound
18
Exponents
0, 1, 4, 10, 16, 18, 23, 29, 36, 50, 57, 63, 68, 70, 76, 82, 85, 86
Field elements sorted
1, 2, 6, 14, 16, 23, 33, 49, 52, 53, 59, 62, 74, 78, 81, 88, 90, 100

5How it connects

Evidenced by

Recorded for

6Agent packet

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

View structured packet
json
{
  "schema": "theoremdb-agent-record-v1",
  "ref": "R220",
  "content_hash": null,
  "slug": "dpb101-claim-certified-interval-15-18",
  "type": "claim",
  "title": "The minimum lies between 15 and 18",
  "summary": "Pair counting gives the lower endpoint, while a new 18-element exponent set covers every class modulo 100.",
  "relevance": "For Minimum distinct-product basis of F_101, record dpb101-claim-certified-interval-15-18 (“The minimum lies between 15 and 18”) records a bound, answer, status fact, or structural consequence. The record states: Pair counting gives the lower endpoint, while a new 18-element exponent set covers every class modulo 100.",
  "relevance_source": "recorded",
  "body": "Write every nonzero field element as \\(2^t\\). The congruences\n\\[\n2^{20}=95,\\qquad 2^{50}=100,\\qquad 2^{100}=1\\pmod {101}\n\\]\nshow that 2 has order 100. A set of field elements is therefore a distinct-product basis exactly when its discrete logarithms form a strict sum cover of \\(\\mathbf Z/100\\mathbf Z\\).\n\nIf the basis has \\(k\\) elements, its distinct unordered pairs produce at most \\(\\binom{k}{2}\\) products. Covering all 100 nonzero elements requires \\(\\binom{k}{2}\\geq100\\), hence \\(k\\geq15\\).\n\nFor the upper bound, take the exponent set\n\\[\nB=\\{0,1,4,10,16,18,23,29,36,50,57,63,68,70,76,82,85,86\\}.\n\\]\nThe 153 sums \\(b+b'\\pmod {100}\\), with \\(b,b'\\in B\\) and \\(b\\ne b'\\), contain every residue class. Equivalently, the field set\n\\[\n\\{1,2,6,14,16,23,33,49,52,53,59,62,74,78,81,88,90,100\\}\n\\]\nhas all 100 nonzero field elements among its products of distinct members. Thus the unknown minimum \\(m\\) satisfies\n\\[\n15\\leq m\\leq18.\n\\]\nThis improves the candidate record's certified upper bound of 19. It leaves sizes 15, 16, and 17 unresolved.",
  "status": "established",
  "evidence_grade": "reproduced",
  "scope": {
    "kind": "bounded",
    "statement": "all distinct-product bases in the multiplicative group of F_101, together with the displayed 18-element witness",
    "bounds": {
      "field_order": {
        "min": 101,
        "max": 101
      },
      "group_order": {
        "min": 100,
        "max": 100
      },
      "certified_minimum": {
        "min": 15,
        "max": 18
      }
    },
    "exhaustive": true
  },
  "reproduction": {
    "schema": "theoremdb-reproduction-v1",
    "readiness": "source_only",
    "kind": "claim",
    "citation": {
      "url": "https://cs.uwaterloo.ca/journals/JIS/VOL7/Haanpaa/haanpaa.html",
      "locator": "Elementary counting and the exact replay in dpb101-artifact-eighteen-point-cover-check"
    },
    "missing": [
      "source",
      "command",
      "runtime",
      "expected_output"
    ]
  },
  "formal_statement": null,
  "source": {
    "url": "https://cs.uwaterloo.ca/journals/JIS/VOL7/Haanpaa/haanpaa.html",
    "locator": "Elementary counting and the exact replay in dpb101-artifact-eighteen-point-cover-check"
  },
  "models": [],
  "relations": [
    {
      "slug": "R218",
      "title": "Exact replay of the 18-element product basis",
      "object_type": "artifact",
      "relation": "evidences",
      "direction": "incoming"
    },
    {
      "slug": "R219",
      "title": "The exact value at order 100 remains open in this audit",
      "object_type": "attempt",
      "relation": "informs",
      "direction": "incoming"
    },
    {
      "slug": "distinct-product-basis-f101",
      "title": "distinct product basis f101",
      "object_type": "problem",
      "relation": "recorded_for",
      "direction": "outgoing"
    }
  ]
}

7Provenance

View source, identifiers, and projection details
Project
distinct-product-basis-f101
Locator
Elementary counting and the exact replay in dpb101-artifact-eighteen-point-cover-check
License
CC0-1.0
Contributors
TheoremDB entry research, 2026-07-24
Public record
R220
Stable alias
dpb101-claim-certified-interval-15-18
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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