## 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, June 28, 2019 — 2:30 PM EDT

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

"Heat Flow of Isometric G2-structures"

Thursday, June 27, 2019 — 10:00 AM EDT

**Luke MacLean, Department of Pure Mathematics, University of Waterloo**

"Different extensions of first-order logic"

How does one capture the properties that aren’t definable by first-order sentences or even theories? One way is to allow infinitary conjunctions of first-order sentences. Another is to expand the language that is being used. In this talk I will discuss the cases when these two extensions coincide, and sketch a proof by W. Craig and R.L. Vaught that a computably axiomatizable theory can be finitely axiomatized using additional predicates.

Wednesday, June 26, 2019 — 4:00 PM EDT

**Carlos Valero, Department of Pure Mathematics, University of Waterloo**

"Why we Caré about the Poincaré Conjecture?"

Monday, June 24, 2019 — 2:30 PM EDT

**Roger Smith, Texas A&M University**

"A Galois correspondence for crossed products"

We consider a discrete group *G* acting by outer automorphisms on a simple unital C*-algebra *A*. We address the problem of characterising the C*-algebras lying between *A* and its crossed product by *G*. The main result is that these are parameterised by the subgroups of *G*. This is joint work with Jan Cameron.

MC 5417

Thursday, June 20, 2019 — 4:00 PM EDT

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

"The Parallel Postulate: a 2000-year controversy"

Thursday, June 20, 2019 — 10:00 AM EDT

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

"The Isomorphism Problem of the Class of Computable Trees of Finite Rank"

Friday, June 14, 2019 — 10:30 AM EDT

**Samuel Harris, Department of Pure Mathematics, University of Waterloo**

"Applying unitary correlations to matrix-valued Tsirelson correlations"

In this talk we’ll explore another application of unitary correlations. We’ll use C*-algebraic analogues of quantum teleportation and super-dense coding to transform non-spatial unitary correlations into a matrix version of non-spatial Tsirelson correlations. On the way, we’ll also find some separations for matrix-valued Tsirelson correlations between the quantum and the quantum spatial models.

Thursday, June 13, 2019 — 12:00 PM EDT

**Jeff Samuelson, Department of Pure Mathematics, University of Waterloo**

"A variety of schemes, part II"

We give the general definition of schemes and discuss several examples.

MC 5479

Thursday, June 13, 2019 — 10:00 AM EDT

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

**"**Computability Theory and Some Applications"

Wednesday, June 12, 2019 — 3:00 PM EDT

**Valentina Harizanov, George Washington University**

"Arithmetically categorical structures**"**

Tuesday, June 11, 2019 — 2:30 PM EDT

**Sylvie Davis, Department of Pure Mathematics, University of Waterloo**

"Monoids, Computation, and the State Complexity of Regular Languages"

Tuesday, June 11, 2019 — 2:00 PM EDT

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

"Approximation Constants for Closed Subschemes of Projective Varieties"

Tuesday, June 11, 2019 — 12:00 PM EDT

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

"A variety of schemes"

in this talk we will define schemes. We will see some examples of schemes that are not affine schemes. Next, we will study properties of locally ringed spaces and stalks of schemes along with their residue fields. Finally, we will see how to glue schemes and depending on the gluing we can have different types of schemes.

MC 5479

Tuesday, June 11, 2019 — 9:30 AM EDT

**Christopher Lang, Department of Pure Mathematics, University of Waterloo**

"The ADHM-Nahm Procedure"

In my last talk, we examined how group actions simplify the Nahm equations. In this talk, we outline the procedure that generates monopoles from solutions of these equations, the ADHM-Nahm procedure. Then, using Maple,, we follow this procedure to generate explicit examples of monopoles.

**Spencer Whitehead, Department of Pure Mathematics, University of Waterloo**

'Decorated Coxeter Diagrams'

Thursday, June 6, 2019 — 12:00 PM EDT

**Carlos Valero, Department of Pure Mathematics, University of Waterloo**

"Ask Sheeves"

This will be a continuation of Tuesday's talk.

MC 5479

Tuesday, June 4, 2019 — 1:30 PM EDT

**Anton Mosunov, Department of Pure Mathematics, University of Waterloo**

"Absolute Bounds on the Number of Solutions of Certain Equations of Thue and Thue-Mahler Type"

Let $F(X, Y)$ be an irreducible polynomial with integer coefficients of degree at least three. In 1909 it was proved by Thue that the Diophantine equation

$$F(x, y) = m,$$

Tuesday, June 4, 2019 — 12:00 PM EDT

**Jeffrey Samuelson, Department of Pure Mathematics, University of Waterloo**

"An Agrarian Interlude"

Tuesday, June 4, 2019 — 9:30 AM EDT

**Speaker 1: Patrick Naylor, Department of Pure Mathematics, University of Waterloo**

"Handles and Kirby diagrams"

Ever wanted to represent a manifold with a diagram? Via several examples, this talk will explain how low dimensional manifolds and the relationships between them can be described by Kirby diagrams. We will review the necessary Morse theory to describe handle decompositions, and then use this to draw many pictures.

**Speaker 2: Jason d'Eon, Department of Pure Mathematics, University of Waterloo**

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