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Indexed by:期刊论文

Date of Publication:2017-01-01

Journal:JOURNAL OF KNOT THEORY AND ITS RAMIFICATIONS

Included Journals:SCIE

Volume:26

Issue:1

ISSN No.: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.