An estimate of the unknotting numbers for virtual knots by forbidden moves

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It is known that any virtual knot can be deformed into the trivial knot by a finite sequence of forbidden moves. In this paper, we give the difference of the values obtained from some invariants constructed by Henrich between two virtual knots which can be transformed into each other by a single forbidden move. As a result, we obtain a lower bound of the unknotting number of a virtual knot by forbidden moves.

Original languageEnglish
Article number13500090
JournalJournal of Knot Theory and its Ramifications
Issue number3
Publication statusPublished - 2013 Mar 1
Externally publishedYes



  • forbidden move
  • unknotting number
  • Virtual knot

ASJC Scopus subject areas

  • Algebra and Number Theory

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