Topology Seminar

Gordian Knots According to the legend of Phrygian Gordium, Alexander the Great cut the ``Gordian Knot’’ and eventually went on to rule Asia thereby fulfilling an ancient prophecy.  Where there are several descriptions of the precise nature of the Gordian Knot and Alexander’s action, an explicit mathematical treatment (the theory of thick knots) and the reasons […]

TBA

Sam Nelson will wow us with his maths.

Robert Bowden will tell us fantastic things he did at PSU.

Jim Hoste will do an interpretive knot dance.

Title: Untying Knots with Neural Nets Abstract: Neural networks can transform 3-dimensional data in a manner reminiscent of an ambient isotopy. With some modifications, a neural network can be trained to manipulate the vertices of a knot while respecting its topological structure. We use the discrete Mo ̈bius energy as a loss function to incentivize […]

In this talk I will recount the history of my knot theory-based music project and show an example of my method for creating music from knot homsets.

M. Niebrzydowski and J. H. Przytycki defined a Kauffman bracket magma and constructed the invariant P of framed links in 3-space. The invariant is closely related to the Kauffman bracket polynomial. The normalized bracket polynomial is obtained from the Kauffman bracket polynomial by the multiplication of indeterminate and it is an ambient isotopy invariant for […]

(Joint with Ichihara, Jong, and Saito). We show that two-bridge knots admit no purely cosmetic surgeries, ie no pair of distinct Dehn surgeries on such a knot produce 3-manifolds that are homeomorphic as oriented manifolds. Our argument is based on a recent result by Hanselman and a study of signature and finite type invariants of […]

We talk about building knots using mosaics which were as introduced as a way of modeling quantum knots by Lomonaco and Kauffman and a newer variant, hexagonal mosaics, introduced by Jennifer McLoud-Mann. In the process we find a new bound on crossing numbers for hexagonal mosaics and find an infinite family of knots which do […]

The Jones polynomial is an invariant of knots in R^3. Following a proposal of Witten, it was extended to knots in 3-manifolds by Reshetikhin-Turaev using quantum groups. Khovanov homology is a categorification of the Jones polynomial of a knot in R^3, analogously to how ordinary homology is a categorification of the Euler characteristic of a […]