Seminars and Colloquia by Series

From walls to cube complexes by Abdul Zalloum

Series
Geometry Topology Seminar Pre-talk
Time
Monday, September 19, 2022 - 13:00 for 1 hour (actually 50 minutes)
Location
Speaker
Abdalrazzaq (Abdul) ZalloumUniversity of Toronto

A geodesic metric space is said to be CAT(0) if triangles are at most as fat as triangles in the Euclidean plane. A CAT(0) cube complex is a CAT(0) space which is built by gluing Euclidean cubes isometrically along faces. Due to their fundamental role in the resolution of the virtual Haken's conjecture, CAT(0) cube complexes have since been a central object of study in geometric group theory and their study has led to ground-breaking advances in 3–manifold theory. The class of groups admitting proper cocompact actions on CAT(0) cube complexes is very broad and it includes hyperbolic 3-manifolds, most non-geometric 3 manifold groups, small cancelation groups and many others. 

 

A revolutionary work of Sageev shows that the entire structure of a CAT(0) cube complexes is encoded in its hyperplanes and the way they interact with one another. I will discuss Sageev's theorem which provides a recipe for constructing group actions on CAT(0) cube complexes using some very simple and purely set theoretical data.

From little things big things grow by Tyrone Ghaswala

Series
Geometry Topology Seminar Pre-talk
Time
Monday, March 22, 2021 - 13:00 for 1 hour (actually 50 minutes)
Location
ONLINE
Speaker
Tyrone GhaswalaCIRGET, Université du Québec à Montréal

This pre-talk will be an introduction to infinite-type surfaces and big mapping class groups. I will have a prepared talk, but it will be extremely informal, and I am more than happy to take scenic diversions if the audience so desires!

Algebraic definitions for string topology

Series
Geometry Topology Seminar Pre-talk
Time
Monday, February 17, 2020 - 12:45 for 1 hour (actually 50 minutes)
Location
Skiles 006
Speaker
Kate PoirierCUNY - City College of Technology

String topology studies various algebraic structures given by intersecting loops in a manifold, as well as those on the Hochschild chains or homology of an algebra. In this preparatory talk, we survey a collection of such structures and their relationships with one another.

Pre-talk for "The coalgebra of singular chains and the fundamental group"

Series
Geometry Topology Seminar Pre-talk
Time
Monday, January 27, 2020 - 12:45 for 1 hour (actually 50 minutes)
Location
Skiles 006
Speaker
Manuel RiveraPurdue

In the first talk I will introduce the main constructions, many of which are classical, from scratch. This part will be introductory and accessible to a general audience with a basic knowledge of topology. This introduction will also serve as preparation for the main talk in which I will outline the proof and discuss some applications.

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