## 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

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