{
  "abstract": "We give a tight single-change covering design with $v=26$ and $k=6$. This answers Problem 1 of the Nineteenth British Combinatorial Conference, which asked whether such a design exists with block size greater than $5$. We also describe the satisfiability search that found the design, including negative search results at the smallest admissible order $v=21$.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2607.10978",
  "author_total": 1,
  "authors": [
    {
      "name": "Richard Bean"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/1wkr5h1pfbegx.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2607.10978",
  "fulltext_url": null,
  "id": "1wkr5h1pfbegx",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2607.10978",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "cs.DM"
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    [
      "arxiv",
      "math.CO"
    ],
    [
      "openalex",
      "2607|Advanced Combinatorial Mathematics"
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  ],
  "openalex": "W7168288631",
  "pdf_url": "https://arxiv.org/pdf/2607.10978",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-07",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/1wkr5h1pfbegx.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:27:42Z",
      "native_id": "2607.10978",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2607.10978"
    }
  ],
  "subjects": [
    {
      "field": "mathematics",
      "origin": "arxiv:math.CO",
      "subfield": "combinatorics"
    }
  ],
  "title": "A tight single-change covering design with block size 6",
  "title_text": "A tight single-change covering design with block size 6",
  "type": "preprint",
  "updated_at": "2026-10-30T12:27:42Z",
  "url": "https://research.draconitic.com/paper/1wkr5h1pfbegx",
  "venue": "arXiv",
  "versions": []
}