## 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

Friday, March 31, 2017 — 3:30 PM EDT

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

"The Jacobson Radical of Certain Semicrossed Products"

We study the Jacobson radical of the semicrossed product $A\times_\alpha P$ when $A$ is a simple C*-algebra and $P$ is either a subsemigroup of an abelian group or a free semigroup. A full characterization is obtained for a large subset of these semicrossed products and we apply our results to a number of examples.

MC 5417

Friday, March 31, 2017 — 2:30 PM EDT

**Ben Sibley, Simons Center, Stony Brook University**

"Limits and bubbling sets for the Yang-Mills flow on Kaehler manifolds"

Friday, March 31, 2017 — 11:30 AM EDT

**Stephen Lazzaro, University of Waterloo**

"Continuous model theory X"

We begin chapter 8 of *Model theory for metric structures*: a discussion of types in the continuous setting.

MC 5403

Thursday, March 30, 2017 — 4:00 PM EDT

**Anton Mosunov (Pure Mathematics) and Luis Antonio Ruiz (Combinatorics & Optimization), University of Waterloo**

"Tomato Packing and Lettuce-Based Crypto"

Lettuce is good for you. Lattices are good for humanity. We are going to present some nutritious facts about lattices and convince you that they are good for your mathematical diet. Anton will explain the importance of lattices in the tomato/orange/sphere packing problem, and Antonio will show you that many portions of lattices a day may keep you safe from quantum hackers.

MC 5501

Thursday, March 30, 2017 — 3:00 PM EDT

**Christopher Hawthorne and Wilson Cheung, University of Waterloo**

"Topos theory XVII"

We finish chapter 10: a proof of the completeness theorem of topoi for intuitionist logic, and some applications. We begin chapter 11 of Goldblatt: a discussion of categorical generalizations of quantifiers.

MC 5413

Thursday, March 30, 2017 — 1:30 PM EDT

**Oleksiy Klurman, University College London**

"Multiplicative functions over the function fields"

Thursday, March 30, 2017 — 12:30 PM EDT

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

"The Quasi-Separation Continues"

This week, we'll continue working through topological properties of schemes. In particular, we'll look at quasiseparated, reduced, and integral schemes, and the various relations amongst these properties. Keeping in the spirit of last week, we should finish our tour of the "gallery of observations" of these properties, and with it Section 5.3.

MC 5479

Tuesday, March 28, 2017 — 3:00 PM EDT

**Jonny Stephenson, Department of Pure Mathematics, University of Waterloo**

"The c.e. embeddability condition"

We will discuss the c.e. embeddability condition, which is a condition introduced by Richter, and which provides an exact characterization of those structures which do not code any non-c.e. sets. Such structures cannot have nontrivial Turing or enumeration degrees. If time permits, we will demonstrate that linear orderings have the c.e. embeddability condition.

MC 5403

Tuesday, March 28, 2017 — 11:00 AM EDT

**Mohammad Mahmoud, University of Waterloo**

"On the Computable Categoricity of Trees of Finite Height"

Friday, March 24, 2017 — 3:30 PM EDT

**Ali Kavruk, Virginia Commonwealth University**

"Christandl's Problem and Connes' Embedding Problem"

Friday, March 24, 2017 — 3:30 PM EDT

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

"Affine and Projective Planes"

Friday, March 24, 2017 — 2:30 PM EDT

**Charlotte Kirchoff-Lukat, University of Cambridge**

"Lagrangian branes with boundary in stable generalised complex manifolds"

Thursday, March 23, 2017 — 1:30 PM EDT

**Roger Baker, Brigham Young University**

"Quadratics over the primes"

Let ||...|| denote distance from the nearest integer. Let f be a quadratic polynomial with irrational leading coefficient. We give a new result on small values of ||f(p)|| for infinitely many primes p. One technique that is used involves a lemma of Birch and Davenport on a real number with many rational approximations, and I will try to explain the role of this lemma in the work.

M3 3103

Thursday, March 23, 2017 — 12:30 PM EDT

**Nickolas Rollick, Department of Pure Mathematics, University of Waterloo**

"A quasi-separated talk"

Tuesday, March 21, 2017 — 3:00 PM EDT

**Jonny Stephenson, Department of Pure Mathematics, University of Waterloo**

"1-generic presentations and r.i.c.e. sets"

We will conclude our study of 1-generic presentations by showing that there is a strong link between 1-genericity and r.i.c.e sets. In particular, we will see that if A is a 1-generic presentation, then the sets which are c.e. in D(A) are precisely those which are r.i.c.e.

MC 5403

Monday, March 20, 2017 — 4:00 PM EDT

**Jesse Peterson, Vanderbilt University**

"Connes’ character rigidity conjecture for lattices in higher rank groups"

Monday, March 20, 2017 — 11:30 AM EDT

**Cam Marcott, Department of Combinatorics & Optimization, University of Waterloo**

We define matroidal flips, which will be the primary inductive tool for proving the Hodge-Riemann relations and the Hard Lefschetz Theorem for matroids. Time permitting, we will begin to prove these things.

MC 5403

Monday, March 20, 2017 — 11:30 AM EDT

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

"NIP, Keisler Measures and Combinatorics"

We continue with Starchenko¹s Bourbaki paper, beginning now to look at the application to combinatorics.

MC 5413

Friday, March 17, 2017 — 3:30 PM EDT

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

"Local dimensions of self-similar measures with overlap"

Thursday, March 16, 2017 — 1:30 PM EDT

**Anthony McCormick, Department of Pure Mathematics, University of Waterloo**

"The Classification of Simple Lie Algebras Part 1: Roots"

We'll begin proceeding towards our main goal for this semester: the classification of simple Lie algebras (and also simple linear algebraic groups) by Dynkin diagrams. Our first goal is to understand the notion of a root. We will then outline the basic strategy before analyzing the rank one scenario.

MC 5413

Thursday, March 16, 2017 — 12:30 PM EDT

**Brett Nasserden, Department of Pure Mathematics, University of Waterloo**

"The Proj Construction"

The Proj construction is a fundamental tool in algebraic geometry. Following Vakil's exposition we will construct a scheme Proj S from a commutative graded ring S. Time permitting we will discuss some of the properties of Proj S and how it relates to the classical definition of projective space over a field.

MC 5479

Tuesday, March 14, 2017 — 2:30 PM EDT

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

"Generic Reals and Generic Enumerations"

This week we first continue proving results about 1-generics, namely, we will talk about "mutually generic" reals. After that we move to the Generic Enumerations of structures where we decide r.i.c.e. sets on an $\omega$-presentations instead of c.e. sets of finite sequences.

MC 5413

**Note different time and room for this week only.**

Tuesday, March 14, 2017 — 11:00 AM EDT

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

"Jumps, Bounds and Inversions"

In this talk, I will explain some basic results about jump inversion as applied to a non-standard reducibility, the bounded Turing reduction. We will see that some standard results fail, and attempt to remedy this by modifying the jump operator to make it more compatible with the reduction. Along the way, we will encounter the Ershov hierarchy, problems with relativization, and a frightening definition.

MC 5403

Monday, March 13, 2017 — 4:00 PM EDT

**Dan Edidin, University of Missouri**

"Algebraic Geometry and the Phase Retrieval Problem"

Friday, March 10, 2017 — 3:30 PM EST

**Adam Fuller, Ohio University**

"Boundary Representations of Operator Spaces"

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