Junior Topology and Group Theory Seminar

Please note that the list below only shows forthcoming events, which may not include regular events that have not yet been entered for the forthcoming term. Please see the past events page for a list of all seminar series that the department has on offer.

Past events in this series
24 October 2018
16:00
Benjamin Brück
Abstract

"Fibre theorems" in the style of Quillen's fibre lemma are versatile 
tools used to study the topology of partially ordered sets. In this 
talk, I will formulate two of them and explain how these can be used to 
determine the homotopy type of the complex of (conjugacy classes of) 
free factors of a free group.
The latter is joint work with Radhika Gupta.

  • Junior Topology and Group Theory Seminar
31 October 2018
16:00
Joseph Scull
Abstract


A core problem in the study of manifolds and their topology is that of telling them apart. That is, when can we say whether or not two manifolds are homeomorphic? In two dimensions, the situation is simple, the Classification Theorem for Surfaces allows us to differentiate between any two closed surfaces. In three dimensions, the problem is a lot harder, as the century long search for a proof of the Poincaré Conjecture demonstrates, and is still an active area of study today.
As an early pioneer in the area of 3-manifolds Seifert carved out his own corner of the landscape instead of attempting to tackle the entire problem. By reducing his scope to the subclass of 3-manifolds which are today known as Seifert fibred spaces, Seifert was able to use our knowledge of 2-manifolds and produce a classification theorem of his own.
In this talk I will define Seifert fibred spaces, explain what makes them so much easier to understand than the rest of the pack, and give some insight on why we still care about them today.
 

  • Junior Topology and Group Theory Seminar
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