CMSA/Tsinghua Math-Science Literature Lecture
Prof. Cameron Gordon will present a lecture in the CMSA/Tsinghua Math-Science Literature Lecture Series.
Date: Wednesday, March 20, 2024
Time: 9:00–10:30 am ET
Location: Room G10, CMSA, 20 Garden Street, Cambridge MA and via Zoom Webinar
Registration is required.
- Register here to attend in person: In-Person Registration
- Register here to attend virtually: Zoom Webinar Registration
Title: The Unknotting Number of a Knot
Abstract: One of the oldest and most natural knot invariants is the unknotting number, which is the minimum number of times a knot must be allowed to pass through itself in order to unknot it. Although this invariant was discussed by Tait almost 150 years ago, it is still poorly understood. For instance it is not known if it is algorithmically computable, and indeed there is an 8-crossing knot whose unknotting number is unknown. Nevertheless, the many developments in knot theory since Tait have led to some understanding of unknotting number, for example through its connection with 4-dimensional topology. We will give a historical account of this progress, and discuss some of the questions that are still open.
Beginning in Spring 2020, the CMSA began hosting a lecture series on literature in the mathematical sciences, with a focus on significant developments in mathematics that have influenced the discipline, and the lifetime accomplishments of significant scholars.