{
  "abstract": "We initiate the study of exotic Dehn twists along 3-manifolds embedded in 4-manifolds.This yields the first known examples of exotic diffeomorphisms of contractible 4-manifolds; more generally, it produces exotic diffeomorphisms of definite 4-manifolds, as well as exotic diffeomorphisms of 4-manifolds (whose boundary is not diffeomorphic to S 3 ) that persist after one stabilization.In particular, we obtain the first example of a diffeomorphism of a contractible 4-manifold that is not isotopic to the identity.We also construct the smallest closed 4-manifold currently known to support an exotic diffeomorphism.These exotic diffeomorphisms arise as Dehn twists along certain Seifert fibered 3-manifolds.As a consequence, we obtain loops of diffeomorphisms of 3-manifolds that extend topologically, but not smoothly, over some 4-manifold X .This implies that the map 1 .Diff.X // ! 1 .Homeo.X // is not surjective.Our method uses Seiberg-Witten theory for a 2-parameter family over RP 2 , whereas previous methods for detecting exotic diffeomorphisms relied on 1-parameter family gauge-theoretic invariants.Using a similar strategy, we also construct a new type of exotic diffeomorphism of 4-manifolds, realized as commutators of diffeomorphisms.",
  "abstract_shown": true,
  "affiliations": [
    "Graduate School of Mathematical Sciences, The University of Tokyo, Tokyo, Japan",
    "Department of Mathematics, Dartmouth College, Hanover, NH, United States",
    "Department of Mathematics, Kyoto University, Kyoto, Japan"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 3,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Hokuto Konno",
      "orcid": "0000-0002-0640-4861"
    },
    {
      "affs": [
        1
      ],
      "name": "Abhishek Mallick",
      "orcid": "0000-0003-2955-7091"
    },
    {
      "affs": [
        2
      ],
      "name": "M. Taniguchi",
      "orcid": "0000-0002-7822-0527"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/7h4nz62g6q6jf.bib",
  "cited_by": 22,
  "doi": "10.2140/gt.2026.30.2395",
  "fulltext_url": null,
  "id": "7h4nz62g6q6jf",
  "issns": [
    "1364-0380",
    "1465-3060"
  ],
  "landing_url": "https://doi.org/10.2140/gt.2026.30.2395",
  "language": "en",
  "licence": "CC-BY",
  "licence_label": "CC BY",
  "licence_source": "journal",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "2608|Geometric and Algebraic Topology"
    ]
  ],
  "openalex": "W4380993714",
  "pdf_url": "https://msp.org/gt/2026/30-6/gt-v30-n6-p09-s.pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-07-31",
  "publisher": "Mathematical Sciences Publishers",
  "ris": "https://research.draconitic.com/paper/7h4nz62g6q6jf.ris",
  "sources": [
    {
      "first_seen": "2026-11-04T13:21:00Z",
      "native_id": "W4380993714",
      "source": "openalex",
      "url": "https://doi.org/10.2140/gt.2026.30.2395"
    }
  ],
  "subjects": [
    {
      "field": "mathematics",
      "origin": "openalex:2608|Geometric and Algebraic Topology",
      "subfield": "geometry-topology"
    }
  ],
  "title": "Exotic Dehn twists on 4-manifolds",
  "title_text": "Exotic Dehn twists on 4-manifolds",
  "type": "peer-reviewed",
  "updated_at": "2026-11-09T13:20:59Z",
  "url": "https://research.draconitic.com/paper/7h4nz62g6q6jf",
  "venue": "Geometry & Topology",
  "versions": []
}