Release Time:2019-03-12  Hits:

Indexed by: Journal Article

Date of Publication: 2017-01-01

Journal: JOURNAL OF KNOT THEORY AND ITS RAMIFICATIONS

Included Journals: SCIE

Volume: 26

Issue: 1

ISSN: 0218-2165

Key Words: Warping degree; descending diagram; unknotting number; quandle; quandle coloring; welded datum; Gordian distance

Abstract: The unknotting number of a welded knot is considered. First, we obtain an upperbound of the unknotting number of a welded knot by using the warping degree method. Further, we introduce a standard welded torus knot with welded datum and obtain an upper bound of the unknotting number by an algorithm with warping degree method. Secondly, we get a lower bound of the unknotting number of a welded knot by Alexander quandle colorings. Finally, we give a definition of Gordian distance for welded knots analogous to the classical case.