Series: Mathematics Colloquium

Date: Thursday, October 18, 2001

Time: 4:30 - 5:30 PM

Place: 102 McAllister Building

Host: Sergei Tabachnikov

Refreshments: 4:00 - 4:30 PM, in 212 McAllister

Speaker: Alexei Sossinski, Independent University of Moscow

Title: Unknotting: New Results About an Old Problem

Abstract: 

Although the unknotting problem (to determine if a knot projection is
that of the unknot) was solved in principle by W. Haken in 1962, the
Haken unknotting algorithm is too complicated for computer
implementation, so that finding an effective unknotting procedure
remains one of the main tasks of knot theory.  Recently there has been
quite a flurry of results in this direction (e.g., Dynnikov,
Birman-Hirsch, Hass-Lagarias-Pippenger, Manturov).  The talk is a
survey of some of these results.