## Contact Info

Pure MathematicsUniversity of Waterloo

200 University Avenue West

Waterloo, Ontario, Canada

N2L 3G1

Departmental office: MC 5304

Phone: 519 888 4567 x43484

Fax: 519 725 0160

Email: puremath@uwaterloo.ca

Tuesday, March 12, 2019 — 12:30 PM EDT

**Brad Rogers, Queen's University**

"Integers in short intervals representable as sums of two squares"

Tuesday, March 12, 2019 — 10:30 AM EDT

**Matt Satriano, Department of Pure Mathematics, University of Waterloo**

"The Main Theorem"

We jump ahead and begin proving the main algebraization theorem of the Bakker-Brunebarbe-Tsimerman paper – Theorem 3.1.

MC 5479

Tuesday, March 12, 2019 — 9:00 AM EDT

**Ragini Singhal, Department of Pure Mathematics, University of Waterloo**

"Deformations of Nearly G_2 instantons - Part 2"

In this talk we will discuss the deformation theory for instantons on seven-manifolds with nearly parallel G_2-structure of type-I. We will see how the space of perturbations of instantons can be identified with the eigenspaces of the Dirac operatior, which can be used to prove that all the irreducible instantons with semisimple structure group are rigid.

MC 5413

Monday, March 11, 2019 — 4:00 PM EDT

**Ellen Kirkman, Wake Forest University**

"The Invariant Theory of Artin-Schelter Regular Algebras"

Friday, March 8, 2019 — 3:00 PM EST

**David R. Pitts, University of Nebraska-Lincoln**

"Cartan Triples"

Cartan MASAs in von Neumann algebras have been well-studied since the pioneering work of Feldman and Moore in the 1970's. The presence of a Cartan MASA in a a given von Neumann algebra $\mathcal{M}$ is useful for understanding the structure of $\mathcal{M}$. Cartan MASAs arise when applying the group measure space construction with a countable group $\Gamma$ acting essentially freely on the measure space $(X,\mu)$.

Thursday, March 7, 2019 — 4:00 PM EST

**Anton Bernshteyn, Carnegie Mellon University**

"Independent sets in algebraic hypergraphs"

Thursday, March 7, 2019 — 12:00 PM EST

**Brett Nasserden, Department of Pure Mathematics, University of Waterloo**

"Quotient singularities"

Singularities of algebraic varieties which are quotients of a vector space by a finite group provide interesting connections between algebraic geometry, representation theory, and group theory. I will discuss this circle of ideas with a focus on applications to algebraic geometry.

MC 5403

Tuesday, March 5, 2019 — 10:30 AM EST

**Brett Nasserden, Department of Pure Mathematics, University of Waterloo**

"Definabilization"

Given an affine variety, scheme, or algebraic space defined over the complex numbers one may construct an associated definable analytic space in a functorial manner. With this definabilization functor in hand it becomes possible to compare categories of algebraic coherent sheaves and definable coherent sheaves. We will explain the constructions above and discuss why it is interesting from a geometric perspective.

MC 5479

Tuesday, March 5, 2019 — 9:00 AM EST

**Ragini Singhal, Department of Pure Mathematics, University of Waterloo**

"Deformations of Nearly G_{2} Instantons"

In this talk we will discuss the deformation theory for instantons on seven-manifolds with nearly parallel G_{2}-structure of type-I. We will see how the space of perturbations of instantons can be identified with the eigenspaces of the Dirac operator, which can be used to prove that all the irreducible instantons with semisimple structure group are rigid.

MC 5413

Monday, March 4, 2019 — 4:00 PM EST

**Michael Jury, University of Florida**

"A Tour of Noncommutative Function Theory"

Thursday, February 28, 2019 — 4:00 PM EST

**Levon Haykazyan, University of Waterloo**

"Pseudo-finite sets and dimension, Part 8"

I'll talk about unimodularity. It was introduced by Hrushovski in early 90s as a generalisation of local finiteness. Unimodularity has recently reappeared in the pseudo-finite setting as a tool to develop intersection theory.

MC 5403.

Wednesday, February 27, 2019 — 3:30 PM EST

**Zack Cramer, University of Waterloo **

“Matrix Algebras with a Certain Compression Property”

Tuesday, February 26, 2019 — 12:30 PM EST

**Erick Knight University of Toronto **

“The ζ3-Pell Equation” Abstract

Tuesday, February 26, 2019 — 10:30 AM EST

**Rahim Moosa, Department of Pure Mathematics, University of Waterloo**

"Etale descent"

Following the Bakker-Brunebarbe-Tsimerman paper, we show that quotients by etale equivalence relations exist for definable analytic spaces.

MC 5479

Friday, February 15, 2019 — 2:30 PM EST

**Alessandro Malusà, University of Saskatchewan**

"Complex AJ conjecture"

Thursday, February 14, 2019 — 5:00 PM EST

****This talk was originally scheduled for February 12; it will now take place on February 14, 2019****

**Nick Manor, Department of Pure Mathematics, University of Waterloo**

"Do the Borromean rings exist?"

Thursday, February 14, 2019 — 12:30 PM EST

**Pat Naylor, Department of Pure Mathematics, University of Waterloo**

"Diagrammatic Methods in Topology"

A recent tool for understanding 4-manifolds is something called a “trisection.” These have the interesting advantage of changing problems about 4-manifolds to problems of combinatorics on surfaces. This talk will be an (accessible) tourist’s guide to some background and similar ideas from low(er) dimensional topology: Heegaard splittings and diagrams. Time permitting, we’ll also introduce a trisection and discuss some recent developments.

Wednesday, February 13, 2019 — 3:30 PM EST

**Sanaz Pooya, Stockholm University**

"On the Baum-Connes assembly map for certain semi-direct products"

Wednesday, February 13, 2019 — 3:30 PM EST

****This seminar has been cancelled and is rescheduled for February 27, 2019****

**Mohammad Mahmoud, Department of Pure Mathematics, University of Waterloo**

"The Isomorphism Problem for Pregeometries"

We continue our proof for showing that the isomorphism problem for rice pregeometries with Condition B is $\Pi^0_3$-hard.

MC 5413

Tuesday, February 12, 2019 — 10:30 AM EST

**Rahim Moosa, Department of Pure Mathematics, University of Waterloo**

"Etale descent"

Following the Bakker-Brunebarbe-Tsimerman paper, we show that quotients by etale equivalence relations exist for definable analytic spaces.

MC 5479

Monday, February 11, 2019 — 4:00 PM EST

**Alex Wright, University of Michigan**

"Dynamics, geometry, and the moduli space of Riemann surfaces"

Thursday, February 7, 2019 — 4:00 PM EST

**[Talk rescheduled from February 6, 2019]**

**Sang-Gyun Youn, Queen's University**

"Sobolev embedding properties on compact matrix quantum groups"

Thursday, February 7, 2019 — 4:00 PM EST

**Abolfazl Alam, Shahid Beheshti University**

"Model Companion for Bounded Theories and some Related Complexity Questions"

Thursday, February 7, 2019 — 3:00 PM EST

**Ross Willard, Department of Pure Mathematics, University of Waterloo**

"Dualizing structures that are necessarily of infinite signature, part 3: the gory details"

In this lecture I will finish Pitkethly’s proof that her schizophrenic pair is in fact a dualizing pair. If time remains, I’ll sketch the proof that the term operations of the algebra are not determined by any finite-signature alter ego.

MC 5403

Wednesday, February 6, 2019 — 3:30 PM EST

**Mohammad Mahmoud, Department of Pure Mathematics, University of Waterloo**

"The Isomorphism Problem for Pregeometries"

We continue our proof for showing that the isomorphism problem for rice pregeometries with Condition B is $\Pi^0_3$-hard.

MC 5413

University of Waterloo

200 University Avenue West

Waterloo, Ontario, Canada

N2L 3G1

Departmental office: MC 5304

Phone: 519 888 4567 x43484

Fax: 519 725 0160

Email: puremath@uwaterloo.ca

University of Waterloo

University of Waterloo

43.471468

-80.544205

200 University Avenue West

Waterloo,
ON,
Canada
N2L 3G1

The University of Waterloo acknowledges that much of our work takes place on the traditional territory of the Neutral, Anishinaabeg and Haudenosaunee peoples. Our main campus is situated on the Haldimand Tract, the land granted to the Six Nations that includes six miles on each side of the Grand River. Our active work toward reconciliation takes place across our campuses through research, learning, teaching, and community building, and is centralized within our Indigenous Initiatives Office.