## 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

Friday, September 30, 2022 — 4:30 PM EDT

**Yuming Zhao, Department of Pure Mathematics, University of Waterloo**

**"Positivity and sum-of-squares"**

Thursday, September 29, 2022 — 2:30 PM EDT

**Izar Alonso Lorenzo, Oxford University**

**"Balanced SU(3)-structures and coclosed $G_2$-structures in cohomogeneity one manifolds"**

Thursday, September 29, 2022 — 1:00 PM EDT

**Sean Monahan, Department of Pure Mathematics, University of Waterloo**

"Colours of horospherical varieties"

We are continuing with the basics of horospherical varieties. In this talk I plan to discuss colours of horospherical varieties, and we will start to see their role in the combinatorial description of horospherical varieties.

This seminar will be held jointly online and in person:

Tuesday, September 27, 2022 — 2:30 PM EDT

**Jerry Wang, Department of Pure Mathematics, University of Waterloo**

**"An improvement to the Schmidt bound"**

Counting number fields of fixed degree and bounded discriminant is a classical question in arithmetic statistics. The problem is known in degrees at most 5. In this talk, we will talk about an improvement to Schmidt's upper bound for general degree n, which beats existing improvements for n up to 94. This is joint work with Manjul Bhargava and Arul Shankar.

This seminar will be held jointly online and in person:

Tuesday, September 27, 2022 — 2:00 PM EDT

**Benoit Charbonneau, Department of Pure Mathematics, University of Waterloo**

**"Hyperkähler structure of bow varieties"**

My aim is to discuss some of the background material necessary to understand the recent paper of Roger Bielawski, Yannic Borchard, and Sergey Cherkis titled “Deformations of instanton metrics” (https://arxiv.org/abs/2208.14936).

MC 5403

Tuesday, September 27, 2022 — 12:30 PM EDT

**Xiao Zhong, Department of Pure Mathematics, University of Waterloo**

**"$p$-Adic interpolation of orbits under rational maps"**

Rivera-Letelier’s characterization of possible analytic uniformizations of $p$-adic analytic maps has played an important role within arithmetic dynamics over the past fifteen years. The characterization is given by a trichotomy of indifferent, attracting and superattracting cases near a fixed point of a map.

Friday, September 23, 2022 — 10:30 AM EDT

**Andy Zucker, Department of Pure Mathematics, University of Waterloo**

**"Polish partition principles and the Halpern-Lauchli theorem"**

Thursday, September 22, 2022 — 1:00 PM EDT

**Sean Monahan, Department of Pure Mathematics, University of Waterloo**

**"Introduction to horospherical varieties"**

We will begin the seminar with an introduction to horospherical varieties. In this talk we will define horospherical varieties, and we will (at least start to) discuss their “colours”.

This seminar will be held jointly online and in person:

Thursday, September 22, 2022 — 10:30 AM EDT

**Rachael Alvir, Department of Pure Mathematics, University of Waterloo**

**"Scott Complexity"**

Tuesday, September 20, 2022 — 2:00 PM EDT

**Paul Cusson, Department of Pure Mathematics, University of Waterloo**

**"Infinite Flag Manifolds and Vector Bundle Filtrations"**

Tuesday, September 20, 2022 — 12:30 PM EDT

****Note: change of meeting time - this seminar will be held from 12:30-1:30 pm.****

**Michael Albanese, Department of Pure Mathematics, University of Waterloo**

**"The Kodaira-Enriques Classification of Surfaces"**

I will give a brief overview of the classification of compact complex surfaces and mention some related results.

This seminar will be held jointly online and in person:

- Room: MC 5403
- Zoom information: Meeting ID: 817 1030 9714; Passcode: 063438

Tuesday, September 20, 2022 — 10:00 AM EDT

**Xingchi Ruan, Department of Pure Mathematics, University of Waterloo**

**"On the Solubility of Diophantine Systems"**

Tuesday, September 13, 2022 — 2:30 PM EDT

This will be an organizational meeting for the Differential Geometry Working Seminar. Please contact Spiro Karigiannis with any questions.

MC 5403

Tuesday, September 13, 2022 — 2:30 PM EDT

**Kevin Hare, Department of Pure Mathematics, University of Waterloo**

**"Matrix based number system"**

Most number systems are of the form $a_k d^k + a_{k-1} d^{k-1} + … + a_0$ where the $a_i$ are taken from a finite set of digits, and $d$ is the base of the number system.

In this talk we will discuss what happens if $d$ is taken to be a $n \times n$ Jordan block and $a_i$ are taken to be vectors.

Tuesday, September 13, 2022 — 1:30 PM EDT

**Organizational Meeting**

The algebraic geometry working seminar is starting up again for the term with a meeting to discuss scheduling. Anyone interested in the seminar but unable to attend the meeting should email Eric at etboulter@uwaterloo.ca with any conflicts. This seminar is primarily aimed at grad students and post docs in algebraic geometry and related fields, but all are welcome to attend.

This seminar will be held jointly online and in person:

Monday, September 12, 2022 — 2:30 PM EDT

**Claude LeBrun, Stony Brook University**

**"Four-Manifolds, Conformal Curvature, and Differential Topology"**

Thursday, September 8, 2022 — 4:00 PM EDT

**Sang-Gyun Youn, Seoul National University**

**"Information-theoretic analysis of covariant quantum channels"**

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 Office of Indigenous Relations.