Department of Mathematics and Statistics

Department of Mathematics and Statistics
Department of Mathematics and Statistics
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Number Theory - Neha Prabhu (Queen's University)

Wednesday, June 20th, 2018

Time: 2:00-3:20p.m.  Place: Jeffery Hall 422

Speaker: Neha Prabhu (Queen's University)


Abstract: For an elliptic curve E over the field of rationals, the distribution of the number of points on E modulo a prime p has been well-studied over the last few decades. A relatively recent study is that of extremal primes for a given curve E. These are the primes p of good reduction for which the number of points on E mod p is either maximal or minimal. If E is a curve with CM, an asymptotic for the number of extremal primes was determined by James and Pollack. The talk will discuss the non-CM case and focus on obtaining upper bounds. This is joint work with C. David, A. Gafni, A. Malik and C. Turnage-Butterbaugh

Number Theory - Francois Seguin

Wednesday, May 30th, 2018

Time: 2:30-3:20p.m.  Place: Jeffery Hall 422

Speaker: Francois Seguin

Title: The complementary two-variable problem.

Abstract: In light of our previous talks concerning the two-variable Artin conjecture, one could ask about a "reverse" or "complementary" analogue. During this talk, we will describe this analogue as well as present a proof due to Schinzel from 1960. We will then discuss how much the proof can be modified to obtain a more precise result.

Probability Seminar - Benson Au (Berkeley)

Wednesday, May 23rd, 2018

Time: 3:30-5:00 p.m.  Place: Jeffery Hall 319

Speaker: Benson Au (Berkeley)

Title: Rigid structures in the universal enveloping traffic space

Abstract:  For a tracial $*$-probability space $(\mathcal{A}, \varphi)$, Cébron, Dahlqvist, and Male constructed an enveloping traffic space $(\mathcal{G}(\mathcal{A}), \tau_\varphi)$ that extends the trace $\varphi$. The CDM construction provides a universal object that allows one to appeal to the traffic probability framework in generic situations, prioritizing an understanding of its structure.

We show that $(\mathcal{G}(\mathcal{A}), \tau_\varphi)$ comes equipped with a canonical free product structure, regardless of the choice of $*$-probability space $(\mathcal{A}, \varphi)$. If $(\mathcal{A}, \varphi)$ is itself a free product, then we show how this additional structure lifts into $(\mathcal{G}(\mathcal{A}), \tau_\varphi)$. Here, we find a duality between classical independence and free independence.

We apply our results to study the asymptotics of large (possibly dependent) random matrices, generalizing and providing a unifying framework for results of Bryc, Dembo, and Jiang and of Mingo and Popa. This is joint work with Camille Male.

Free Probability and Random Matrices Seminar Webpage:

Number Theory - Riley Becker

Wednesday, May 16th, 2018

Time: 2:30-3:20p.m.  Place: Jeffery Hall 422

Speaker: Riley Becker

Title: The Size of Sets with the Property D(n).

Abstract: Let $n$ be a nonzero integer, and suppose $A$ is a set of distinct positive integers for which $ab+n$ is a perfect square for each pair of distinct $a$ and $b$ in $A$. Using a discussion of Andrej Dujella, we will find an upper bound on the size of such a set.

Strength in Numbers: Graduate Workshop in Number Theory

Strength In Numbers Poster

Strength in Numbers: A Graduate Workshop in Number Theory and Related Areas

Dates: Friday, May 11th and Saturday, May 12th, 2018

Venue: Jeffery Hall, Queen's University

This is a two-day workshop aimed primarily at graduate students. Participation is open to all. There are five plenary talks by experts and many contributed talks by graduate students on a topic of their choice. Schedules and abstracts of the talks are attached with this email.

A novel feature of this workshop is a presentation by Prof. Erin Maloney, a psychologist specializing in math anxiety and related areas. The invited speakers will also lead a panel discussion regarding professional development on Saturday. Questions can be submitted here -

More information about the workshop can also be found on the website:

This workshop is sponsored by the Fields institute, the Number Theory Foundation and the department of Mathematics and Statistics, Queen's.

We hope to see you there!
The organizing committee
Neha Prabhu, Siddhi Pathak and Vaidehee Thatte

Number Theory - Seoyoung Kim (Brown University)

Thursday, May 10th, 2018

Time: 2:30-3:20p.m.  Place: Jeffery Hall 422

Speaker: Seoyoung Kim (Brown University)

Title: The density of the terms in an elliptic divisibility sequence having a fixed G.C.D. with their indices.

Abstract: Let $\D=(D_{n})_{n\geq 1}$ be an elliptic divisibility sequence associated to the pair $(E,P)$. For a fixed integer $k$, we define $\A_{E,k}=\{n\geq 1 : \gcd(n,D_{n})=k\}$. We give an explicit structural description of $\A_{E,k}$. Also, we explain when $\A_{E,k}$ has positive asymptotic density using bounds related to the distribution of trace of Frobenius of $E$. Furthermore, with preconditions, we obtain an explicit density for $\A_{E,k}$ using the M\"obius function. The precondition holds when $E$ is a finitely anomalous elliptic curve.

Number Theory - M. Ram Murty (Queen's University)

Wednesday, May 2nd, 2018

Time: 4:00-5:30p.m.  Place: Jeffery Hall 422

Speaker: M. Ram Murty (Queen's University)


Abstract: We will discuss the Rankin-Selberg method as well as the analytic continuation of Eisenstein series that allows us to evaluate special values of modular $L$-series at critical point (in the sense of Deligne).

Probability Seminar - Camille Male (Bordeaux)

Tuesday, April 10th, 2018

Time: 3:30-5:00 p.m.  Place: Jeffery Hall 319

Speaker: Camille Male (Bordeaux)

Title: An introduction to traffic independence

Abstract:  The properties of the limiting non-commutative distribution of random matrices can be usually understood thanks to the symmetry of the model, e.g. Voiculescu's asymptotic free independence occurs for random matrices invariant in law by conjugation by unitary matrices. The study of random matrices invariant in law by conjugation by permutation matrices requires an extension of free probability, which motivated the speaker to introduce in 2011 the theory of traffics. A traffic is a non-commutative random variable in a space with more structure than a general non-commutative probability space, so that the notion of traffic distribution is richer than the notion of non-commutative distribution. It comes with a notion of independence which is able to encode the different notions of non-commutative independence.

The purpose of this task is to present the motivation of this theory and to play with the notion of traffic independence.

Free Probability and Random Matrices Seminar Webpage: