The Dabkowski-Sahi Invariant and 4-Moves for Links

Haruko A. Miyazawa, Kodai Wada, Akira Yasuhara

Research output: Contribution to journalArticlepeer-review


Dabkowski and Sahi defined an invariant of a link in the 3-sphere, which is preserved under 4-moves. This invariant is a quotient of the fundamental group of the complement of the link. It is generally difficult to distinguish the Dabkowski-Sahi invariants of given links. In this paper, we give a necessary condition for the existence of an isomorphism between the Dabkowski-Sahi invariant of a link and that of the corresponding trivial link. Using this condition, we provide a practical obstruction to a link to be trivial up to 4-moves.

Original languageEnglish
JournalUnknown Journal
Publication statusPublished - 2020 May 24


  • 4-move
  • Link
  • Link-homotopy
  • Magnus expansion
  • Welded link

ASJC Scopus subject areas

  • General

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