{
  "abstract": "Elements of the Brauer group $\\operatorname{Br}(S)$ of a variety $S$ have geometric incarnations as étale-projective $S$-bundles, yet producing minimalist constructions of such bundles, which often power arithmetic applications, remains a difficult problem. When $S$ is a K3 surface with Picard rank $1$, we use the birational geometry of moduli spaces of twisted sheaves on $S$ to construct geometric realizations of nontrivial elements of $\\operatorname{Br}(S)$. We recover many known geometric constructions of Brauer classes on K3 surfaces while providing a common moduli-theoretic framework for them. As a by-product, we give a new proof of the period-index theorem for very general K3 surfaces.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.15892",
  "author_total": 3,
  "authors": [
    {
      "name": "Sarah Frei"
    },
    {
      "name": "Jack Petok"
    },
    {
      "name": "Anthony Várilly-Alvarado"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/a9m5rr7mk7dg1.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.15892",
  "fulltext_url": null,
  "id": "a9m5rr7mk7dg1",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.15892",
  "language": null,
  "licence": "CC-BY-NC-ND-4.0",
  "licence_label": "CC BY-NC-ND 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by-nc-nd/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "math.AG"
    ],
    [
      "arxiv",
      "math.NT"
    ],
    [
      "openalex",
      "2608|Algebraic Geometry and Number Theory"
    ]
  ],
  "openalex": "W7213335361",
  "pdf_url": "https://arxiv.org/pdf/2609.15892",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-14",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/a9m5rr7mk7dg1.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:21:29Z",
      "native_id": "2609.15892",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.15892"
    }
  ],
  "subjects": [
    {
      "field": "mathematics",
      "origin": "arxiv:math.AG",
      "subfield": "algebra-number-theory"
    }
  ],
  "title": "Geometric realizations of Brauer classes on K3 surfaces from hyperkähler contractions",
  "title_text": "Geometric realizations of Brauer classes on K3 surfaces from hyperkähler contractions",
  "type": "preprint",
  "updated_at": "2026-10-30T12:21:29Z",
  "url": "https://research.draconitic.com/paper/a9m5rr7mk7dg1",
  "venue": "arXiv",
  "versions": []
}