## 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

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Please note: The University of Waterloo is closed for all events until further notice.

Tuesday, March 31, 2015 — 4:30 PM EDT

**Alan Arroyo, Combinatorics & Optimization, University of Waterloo**

"Jordan Curve Theorem: a proof using graphs."

Jordan Curve Theorem states that every non-self-intersecting closed

Tuesday, March 31, 2015 — 3:30 PM EDT

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

“Ramsey’s Theorem in Reverse Mathematics”

Monday, March 30, 2015 — 1:00 PM EDT

**Jason Bell and Rahim Moosa, Department of Pure Mathematics, University of Waterloo **

“Finale”

We wrap up proof of the approximate group theorem.

Monday, March 30, 2015 1:00 pm MC 5479

** Please note Day and Room**

Friday, March 27, 2015 — 3:30 PM EDT

**Jaspar Wiart, Department of Pure Math, University of Waterloo**

“Operator algebras arising from number theory.”

Friday, March 27, 2015 — 2:30 PM EDT

**Geoffrey Scott, University of Toronto **

“Integrable Systems on Log-Symplectic Manifolds”

Thursday, March 26, 2015 — 4:30 PM EDT

Kamyar Moshksar, Pure Mathematics, University of Waterloo

"Decentralized Communications Networks"

After a brief introduction to the concept of channel capacity and reliable transmission over noisy environments, we focus on a class of interference channels known as decentralized networks. By definition, these are networks with no central controller or direct coordination among existing parties. We show how separate transmitter-receiver pairs learn about the parameters in the underlying affine system model and discuss fundamental limits of communication in this framework.

Tuesday, March 24, 2015 — 3:30 PM EDT

**Michael Deveau, Department of Pure Mathematics**

"Weak König's Lemma over RCA_0"

Since the addition of Konig's Lemma to RCA_0 presented last time proved to be too strong, we will next investigate the addition of Weak Konig's Lemma to RCA_0. To show that this will have strength strictly between RCA_0 and ACA_0, we will spend some time discussing the PA degrees, including an important application of the Low Basis Theorem.

Tuesday, March 24, 2015 — 2:30 PM EDT

**Ian Payne, Department of Pure Mathematics, University of Waterloo **

“A CSP algorithm and some work towards a better one”

Tuesday, March 24, 2015 — 1:00 PM EDT

Jason Bell, Department of Pure Mathematics, University of Waterloo

"Approximate Groups: IX"

We continue to follow van den Dries’ Seminaire Bourbaki article entitled "Approximate Groups [after Hrushovski, and Breuillard, Green, Tao]". The subject involves the interaction of additive combinatorics and model theory.

Monday, March 23, 2015 — 4:00 PM EDT

**Chantal David, Concordia University **

“Zeroes and Zeta Functions and Symmetry: One level density for families of L-functions attached to elliptic curves”

Friday, March 20, 2015 — 3:30 PM EDT

**Safoura Jafar-Zadeh, University of Manitoba **

“Isometric Isomorphisms of Beurling Algebras Associated with Locally Compact Groups”

Friday, March 20, 2015 — 3:30 PM EDT

** Alberto García-Raboso, University of Toronto**

"A twisted nonabelian Hodge correspondence"

The classical nonabelian Hodge correspondence establishes an equivalence between certain categories of flat bundles and Higgs bundles on smooth projective varieties. I will describe an extension of this result to twisted vector bundles. No prior knowledge of the above topics will be assumed: come one, come all! There will be pancakes too.

Friday, March 20, 2015 — 2:30 PM EDT

**Thomas Walpuski, MIT - Massachusetts Institute of Technology **

“G2instantons over twisted connected sums”

Friday, March 20, 2015 — 1:00 PM EDT

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

“Approximate Groups: VIII”

We continue to follow van den Dries Seminaire Bourbaki article entitled Approximate Groups [after Hrushovski, and Breuillard, Green, Tao]. The subject involves the interaction of additive combinatorics and model theory.

MC 5413

Wednesday, March 18, 2015 — 2:30 PM EDT

**Jason Bell, Department of Pure Mathematics, University of Waterloo **

“What is a noncommutative torus, II”

Tuesday, March 17, 2015 — 3:30 PM EDT

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

“(Weak) Konig’s Lemma over RCA0.”

Tuesday, March 17, 2015 — 2:30 PM EDT

**Alexander Wires, Department of Pure Mathematics, University of Waterloo **

“Cubing Finite Taylor Algebras”

I will provide the details showing how finite idempotent Taylor algebras can be character- ized by the hereditary existence of cubed elements. There is a corresponding notion of cube absorption which can be described as Few Subpowers and Absorption Theory in a blender. If there is time, I would like to pose a problem here.

Monday, March 16, 2015 — 1:30 PM EDT

**Adam Dor On, Department of Pure Mathematics University of Waterloo **

''Uniqueness theorems for graph algebras and applications”

This week we will discuss uniqueness of graph algebras up to the existence of a gauge circle action. We will then use this to prove that for graphs with no sources, the graph algebra of the graph is *-isomorphic to the graph algebra of the dual of that graph.

M3-2134

Friday, March 13, 2015 — 3:30 PM EDT

**Alessandro Vignati, York University **

“Amenable Operator Algebras and the Isomorphisms problem”

Friday, March 13, 2015 — 2:30 PM EDT

**Long Li, McMaster University **

“On the convexity of the Mabuchi energy functional along geodesics”

Friday, March 13, 2015 — 1:00 PM EDT

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

“Approximate Groups: VII”

We continue to follow van den Dries Seminaire Bourbaki article entitled Approximate Groups [after Hrushovski, and Breuillard, Green, Tao]. The subject involves the interaction of additive combinatorics and model theory.

MC 5413

Wednesday, March 11, 2015 — 2:30 PM EDT

**Jason Bell, Department of Pure Mathematics, University of Waterloo **

“What is a noncommutative torus?”

Tuesday, March 10, 2015 — 3:30 PM EDT

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

“Introduction to Reverse Mathematics (continued)”

We finish characterizing the ω−modelsofRCA0. If time helps, we continue doing the same for ACA0. If time permits, Michael Deveau will do the same for ACA_0.

MC 5413

Tuesday, March 10, 2015 — 2:30 PM EDT

**Renzhi Song, Department of Pure Mathematics, University of Waterloo **

“Barto’s NU Theorem (continued)”

Monday, March 9, 2015 — 4:00 PM EDT

**Hubert Bray, Duke University **

“The Geometry of the Universe”

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

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.