# Past Events

## Events Search and Views Navigation

## October 2019

### Topology Seminar: Jesse Levitt (USC)

Title: Understanding Structure in the Single Variable Knot Polynomials Abstract: We examine the dimensionality and internal structure of the aggregated data produced by the Alexander, Jones, and Z0 polynomials using topological data analysis and dimensional reduction techniques. By examining several families of knots, including over 10 million distinct examples, we find that the Jones data is well described as a three dimensional manifold, the Z0 data as a single two dimensional manifold and the Alexander data as a collection of two dimensional manifolds. We confirm each of these…

Find out more »### Topology Seminar: Mauricio Gomez Lopez (U. Oregon)

Title: Cobordism Categories and Spaces of Manifolds. Abstract: Cobordisms have been one of the central objects in topology since the pioneering work of Rene Thom, which provided the first link between manifolds and homotopy theory. In more recent years, there has been much focus on cobordism categories. These play a fundamental role in the study of topological quantum field theories and automorphism groups of manifolds. A fundamental result in this field is the theorem of Galatius, Madsen, Tillmann, and Weiss,…

Find out more »## November 2019

### Paper Strip Knots (David Bachman)

I will discuss joint work with Jim Hoste, where we prove that a unique folded strip of paper can follow any polygonal knot with odd stick number. In the even stick number case there are either infinitely many, or none.

Find out more »### Topology Triple-Header!

This triple-header of topology talks will include three speakers: First, Hyeran Cho from The Ohio State University will speak about Derivation of Schubert normal forms of 2-bridge knots from (1,1)-diagrams. In this talk, we show that the dual (1, 1)-diagram of a (1, 1)-diagram (a.k.a. a two pointed genus one Heegaard diagram) D(a, 0, 1, r) with 1 ≤ r < 2a + 1 and gcd(2a + 1, r) = 1 is given by D(1/2r, 0, 2a+1-1/r, 1/r) when 1/r…

Find out more »## December 2019

### Dan Douglas (USC)

Abstract TBA

Find out more »### Ryan Blair (Cal State Long Beach)

Abstract TBA

Find out more »## January 2020

### Stefano Vidussi (UCRiverside)

Title: The BNS invariant of the fundamental group of a surface bundle over a surface. Abstract: We will discuss some new results on the Bieri-Neumann-Strebel invariant of these groups, showing in particular that (with obvious exceptions) they algebraically fiber. As a corollary, we show that for "most" bundles these groups are not coherent.

Find out more »## February 2020

### Tommaso Cremaschi (USC)

Title: Volumes and filling collections of multicurves Abstract: In this talk we will be concerned with links L in a Seifert-Fibered space N such that their projection to the base surface is a collection of curves G in minimal position. After stating a hyperbolization result, for the complement of L, in terms of G we will study the volume of their complement and give combinatorial asymptotics. We will be particularly interested in the case where N is the projective tangent…

Find out more »### Kenneth Millett (University of California, Santa Barbara)

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 for its contemporary interest will be discussed. The first simple example of such a Gordian Knotted Structure supported by a rigorous mathematical analysis will be presented.…

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