## 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, December 11, 2020 — 2:30 PM EST

**Eric Boulter, Department of Pure Mathematics, University of Waterloo**

"Smooth and Compact Moduli Spaces of Sheaves on Kodaira Surfaces"

Thursday, December 10, 2020 — 1:00 PM EST

**Florian Richter, Northwestern University**

"Applications of Ergodic Theory to Combinatorics and Number Theory"

Wednesday, December 9, 2020 — 1:00 PM EST

**Jiuya Wang, Duke University**

"The Distribution of Class Groups of Number Fields"

Class group is a central object of the study in number theory. We will give an overview on new developments in the distribution of class groups with a fixed Galois group. In particular, we will explain the use of symmetry which has been overlooked for decades, but turns out to be an essential tool to obtain many new results on the distribution of class groups.

A post-colloquium meet and greet will be held at 2:00 pm using the same Zoom meeting link.

Wednesday, December 9, 2020 — 11:00 AM EST

**Caleb Suan, Department of Pure Mathematics, University of Waterloo**

"Differential Operators on Manifolds with $G_2$-Structure"

Tuesday, December 8, 2020 — 1:00 PM EST

**Alex Weekes, University of British Columbia**

"Nilpotent orbits and affine Grassmannians"

Monday, December 7, 2020 — 1:00 PM EST

**Daren Cheng, Department of Pure Mathematics, University of Waterloo**

"Stable minimal surfaces in R4"

Thursday, December 3, 2020 — 4:00 PM EST

**Mani Thamizhazhagan, Department of Pure Mathematics, University of Waterloo**

"On the interplay of harmonic analysis, combinatorics, additive number theory and ergodic theory"

Thursday, December 3, 2020 — 1:00 PM EST

**Elana Kalashnikov, Harvard University**

"Quiver flag varieties and mirror symmetry"

Wednesday, December 2, 2020 — 1:00 PM EST

**Sherry Gong, Stanford University**

"Invariants of knots and links"

We give an overview of some invariants to distinguish knots and links, and discuss some particular algebraic and geometric invariants. We discuss how these invariants relate to the smooth 4-dimensional Poincare conjecture, one of the most important questions in 4-manifold topology.

A post-colloquium meet and greet will be held at 2:00 pm using the same Zoom meeting link.

Tuesday, December 1, 2020 — 1:00 PM EST

**Junliang Shen, MIT**

"The P=W conjecture and hyper-Kähler geometry"

The P=W conjecture by de Cataldo, Hausel, and Migliorini suggests a surprising connection between the topology of Hitchin systems and Hodge theory of character varieties. In this talk, we will focus on interactions between topology of Lagrangian fibrations and Hodge theory in general hyper-Kaehler geometries. Such connections shed new light on both the P=W conjecture for Hitchin systems and the Lagrangian base conjecture for compact hyper-Kähler manifolds.

Monday, November 30, 2020 — 4:00 PM EST

**Jonathan Zhu, Princeton**

"Mean curvature flow and explicit Łojasiewicz inequalities"

Friday, November 27, 2020 — 2:30 PM EST

**Brady Ali Medina, Department of Pure Mathematics, University of Waterloo**

"A different way to generalize the Weierstrass semigroup"

Friday, November 27, 2020 — 1:00 PM EST

**Michael Brannan, Texas A&M University**

"Quantum symmetries of graphs"

Thursday, November 26, 2020 — 4:00 PM EST

**Caleb Suan, Department of Pure Mathematics, University of Waterloo**

"Intro to Knots and Knot Invariants"

Thursday, November 26, 2020 — 1:00 PM EST

**Lei Alice Chen, California Institute of Technology**

"Actions of Homeo and Diffeo groups on manifolds"

In this talk, I discuss the general question of how to obstruct and construct group actions on manifolds. I will focus on large groups like Homeo(M) and Diff(M) about how they can act on another manifold N. The main result is an orbit classification theorem, which fully classifies possible orbits. I will also talk about some low dimensional applications and open questions. This is a joint work with Kathryn Mann.

Wednesday, November 25, 2020 — 2:30 PM EST

**Yifeng Huang, University of Michigan - Ann Arbor**

"A generating function for counting mutually annihilating matrices over a finite field"

Monday, November 23, 2020 — 4:00 PM EST

**Gigliola Staffilani, MIT**

"The many faces of dispersive equations"

Friday, November 20, 2020 — 2:30 PM EST

**Ákos Nagy, University of California Santa Barbara**

"The asymptotic geometry of G_2-monopoles"

Wednesday, November 18, 2020 — 10:00 AM EST

**Seda Albayrak, Department of Pure Mathematics, University of Waterloo**

"Sparse Automatic Sets"

I will present results in the theory of sparse automatic sets in three different contexts: the theory of algebraic power series, unlikely intersections, and the theory of representations in additive bases.

Online

Friday, November 13, 2020 — 2:30 PM EST

**Joe Driscoll, University of Leeds**

"Deformations of Asymptotically Conical G2-Instantons"

Tuesday, November 3, 2020 — 11:00 AM EST

**Chris Sangwin, University of Edinburgh**

**"Assessing students' proofs online"**

In this seminar I will describe how we, at the University of Edinburgh, have tried to help students learn proof through online assessment. This is ongoing work, driven by a practical need and constrained by current technology which cannot automatically assess students' free form proof. The seminar will discuss the nature of elementary proof more generally.

Monday, November 2, 2020 — 4:00 PM EST

**Andreas Thom, Technische Universität Dresden**

"Finitary approximation properties of groups"

Motivated by the study of equations over groups, I will explain various finitary approximation properties of groups. Related to this, old questions of Ulam will reappear and we will motivate and discuss the notion of stability of solutions and almost solutions to algebraic equations.

Zoom meeting: https://zoom.us/j/92568762391?pwd=djh2Q2R6OFlHbUtCUEZsbE42ZDhxZz09

Wednesday, October 28, 2020 — 2:00 PM EDT

**Seda Albayrak, Department of Pure Mathematics, University of Waterloo**

"A refinement of Christol’s theorem"

Monday, October 19, 2020 — 4:00 PM EDT

**Sergey Grigorian, University of Texas Rio Grande Valley**

"Smooth loops"

Friday, October 9, 2020 — 2:30 PM EDT

**Niky Kamran, McGill University**

"Non-uniqueness for the anisotropic Calderon problem"

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.