## Contact Info

Pure MathematicsUniversity of Waterloo

200 University Avenue West

Waterloo, Ontario, Canada

N2L 3G1

Departmental office: MC 5304

Phone: 519 888 4567 x33484

Fax: 519 725 0160

Email: puremath@uwaterloo.ca

Monday, October 23, 2017 — 4:00 PM EDT

**Damien Roy, University of Ottawa**

"Diophantine curiosities"

Friday, October 20, 2017 — 3:30 PM EDT

**Yiu-Tung Poon, Iowa State University**

"(*p*,*q*) Matricial Range and Quantum Information Science"

Friday, October 20, 2017 — 2:30 PM EDT

**Esther Cabezas-Rivas, Universität Frankfurt**

"Ricci flow beyond non-negative curvature conditions"

We generalize most of the known Ricci flow invariant non-negative curvature conditions to less restrictive negative bounds that remain sufficiently controlled for a short time.

Thursday, October 19, 2017 — 3:30 PM EDT

**Justin Laverdure, Department of Pure Mathematics, University of Waterloo**

"A finite pointed group with no finite basis, Part 1"

We'll go over a construction of Roger Bryant, by building a finite pointed group (P,p) with no finite basis for its laws, as far as we can go. We'll recap basic equational theory stuff, then wade knee-deep into semidirect products and counting arguments.

MC 5413

Thursday, October 19, 2017 — 2:30 PM EDT

**Adam Dor On, Technion**

"Cuntz-Nica-Pimsner algebras over $\mathbb{N}^d$"

An effective model for encoding multivariable dynamical systems via C*-algebras is given by Toeplitz-Nica-Pimsner algebras introduced by Fowler. In the work of Carlsen, Larsen, Sims and Vitadello, the right notion of a "boundary quotient" *Cuntz*-Nica-Pimsner algebra is established, but the precise relations between minimal generators are sometimes very difficult to ascertain.

Thursday, October 19, 2017 — 1:30 PM EDT

**John Friedlander, University of Toronto**

"Exceptional characters and their consequences"

We review some history about the possible existence of certain Dirichlet characters which might possess a zero very close to the line $Re s = 1$ and the remarkably strong consequences which could be derived under the assumption of their existence.

MC 5501

Wednesday, October 18, 2017 — 3:30 PM EDT

**Sascha Troscheit, Department of Pure Mathematics, University of Waterloo**

"Branching Processes, Martingales, Kingman’s Subadditive Ergodic Theorem, and some applications, Part III: The probability of deviating from the mean behaviour"

Tuesday, October 17, 2017 — 4:00 PM EDT

**Levon Haykazyan, Department of Pure Mathematics, University of Waterloo**

"Introduction to Positive Logic"

Tuesday, October 17, 2017 — 1:30 PM EDT

**Diana Castaneda Santos, Department of Pure Mathematics, University of Waterloo**

"Review (Episode 3)"

We will continue our review of schemes. We will mention some examples of schemes that are not affine schemes. We will review the proj construction, and more topological properties of schemes. If time permits we'll define morphisms of schemes.

MC 5413

Monday, October 16, 2017 — 4:00 PM EDT

**Karen Yeats, Department of Combinatorics & Optimization, University of Waterloo**

"Chord diagram expansions in quantum field theory"

Over the last few years we have been able to re-expand certain series in perturbative quantum field theory using chord diagrams. These new expansions have nice mathematical structure. I will give an overview on them and how they can be useful.

MC 5501

Thursday, October 12, 2017 — 3:30 PM EDT

**Andrei Krokhin, Durham University**

"The complexity of valued constraint satisfaction problems"

Wednesday, October 11, 2017 — 3:30 PM EDT

**Rekha Biswal, Université Laval**

"Demazure flags, Chebyshev polynomials and mock theta functions"

Wednesday, October 11, 2017 — 3:30 PM EDT

**Sascha Troscheit, Department of Pure Mathematics, University of Waterloo**

"Branching Processes, Martingales, Kingman’s Subadditive Ergodic Theorem, and some applications, Part II: The almost sure number of descendants and finer information, such as expected deviations from the average behaviour and `immigration'"

Friday, October 6, 2017 — 3:30 PM EDT

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

"Estimates for compression norms and additivity violation in quantum information"

Friday, October 6, 2017 — 2:30 PM EDT

**Ajneet Dhillon, University of Western Ontario**

"Tamagawa numbers and connected components of stacks"

Let X be a smooth projective curve over a finite field and $G$ a semisimple algebraic group over its function field. Let $\mathcal{G}$ be a smooth group scheme over X with generic fiber $G$. The Tamagawa number of $G$ is an arithmetic invariant obtained from a Haar measure on the adelic points of $G$. A conjecture of Harder relates this number to the number of components of the moduli stack of $\mathcal{G}$-bundles.

Thursday, October 5, 2017 — 3:30 PM EDT

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

"An introduction to finite basis problems"

To get us started this term, I will describe some known instances of the finite basis problem in universal algebra, and one unknown instance that is currently bugging me: “Murskii + L'vov.” This will be an elementary lecture, intended as a warm-up for Justin’s lectures later this month.

MC 5413

Thursday, October 5, 2017 — 1:30 PM EDT

"Generalizations of Chebyshev's bias"

Wednesday, October 4, 2017 — 4:30 PM EDT

**Sam Kim, Department of Pure Mathematics, University of Waterloo**

"I'll prove the Fundamental Theorem of Algebra"

Gauss proved that complex polynomials always admit a root. I'll explain how he came to that conclusion and present a proof that rigorizes his argument in a nice way. You will only need to know a little vector calculus and the intermediate value theorem. If we have time, I'll show you why a flat triangle has angles that add up to π and why a triangle on a sphere doesn't.

MC 5501

Wednesday, October 4, 2017 — 3:30 PM EDT

**Sascha Troscheit, Department of Pure Mathematics, University of Waterloo**

"Branching Processes, Martingales, Kingman’s Subadditive Ergodic Theorem, and some applications"

Tuesday, October 3, 2017 — 4:00 PM EDT

**Peter Sinclair, McMaster University **

"Dp-finite fields"

Tuesday, October 3, 2017 — 1:30 PM EDT

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

"The Review Continues"

We'll continue our review from last week. This week, we're actually defining a scheme, as well as giving a quick review of some of the associated topological properties.

MC 5413

Monday, October 2, 2017 — 4:00 PM EDT

****CANCELLED****

**Ragnar-Olaf Buchweitz, University of Toronto**

"The McKay Correspondence Then and Now"

University of Waterloo

200 University Avenue West

Waterloo, Ontario, Canada

N2L 3G1

Departmental office: MC 5304

Phone: 519 888 4567 x33484

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