Department of Mathematics and Statistics

Department of Mathematics and Statistics
Department of Mathematics and Statistics
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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 - https://docs.google.com/forms/d/e/1FAIpQLSdedZpevw4t8mDHlctq1Nmbmz3hX6v6IC-pyeBmV79jlWLM2g/viewform?usp=sf_link

More information about the workshop can also be found on the website: https://sites.google.com/view/strengthinnumbers2018/home

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!
Sincerely,
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)

Title: SPECIAL VALUES OF MODULAR $L$-SERIES.

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:

Department Colloquium - Amie Wilkinson (University of Chicago)

Amie Wilkinson, University of Chicago

Friday, April 6th, 2018

Time: 2:30 p.m.  Place: Jeffery Hall 234

Speaker: Amie Wilkinson, University of Chicago

Title: Robust Mechanisms for Chaos

Abstract: What are the underlying mechanisms for robustly chaotic behavior in smooth dynamics? In addressing this question, I will focus on the study of diffeomorphisms of a compact manifold, where "chaotic" means "mixing" and and "robustly" means "stable under smooth perturbations." I will describe recent advances in constructing and using tools called "blenders" to produce stably chaotic behavior with arbitrarily little effort.

Amie Wilkinson (University of Chicago): Prof. Amie Wilkinson received her BA from Harvard and her Ph.D. from the University of California at Berkeley. After a post-doc at Harvard, she became a professor at North­ western University, where she stayed 13 years, before moving to the University of Chicago in 2012. Prof. Wilkinson is a leading researcher in ergodic theory and dynamical sys­ tems. Among other recognitions of her many achievements, she was an invited speaker at the International Congress of Mathematicians in 2010, was awarded the Satter Prize in Mathematics in 2011, and was elected a fellow of the AMS in 2014. Prof. Wilkinson has also been very active in public outreach, giving numerous public lectures, interviews, and recently publishing an article in the New York Times.

Fields Lecture Series - Amie Wilkinson (University of Chicago)

Amie Wilkinson, University of Chicago

Thursday, April 5th, 2018

Time: 5:30 p.m.  Place: Jeffery Hall 127

Speaker: Amie Wilkinson, University of Chicago

Title: The Mathematics of Deja Vu

Abstract: Dynamics is an area of mathematics concerned with the motion of spaces (" dynamical systems") over time. Dynamics has its roots in the late nineteenth century, when it was developed as a tool to understand physical phenomena, such as the motion of gas molecules in a box and planets around the sun. A simple and yet powerful concept in dynamics is that of recurrence. In everyday language, recurrence is the mathematical version of deja vu: a motion of a space is recurrent if, given enough time, it eventually returns to its original configuration (allowing for a small amount of error). In this talk, I will describe how mathematical results about recurrence can be used to answer surprisingly disparate questions, from the mixing and unmixing of two ideaI gases in a box, to deep properties of the prime numbers, to the discovery of exoplanets in nearby solar systems.

Amie Wilkinson (University of Chicago): Prof Wilkinson (University of Chicago) is a leading researcher in ergodic theory and dynamical systems. Among other recognitions of her many achievements, she was an invited speaker at the International Congress of Mathematicians in 2010, was awarded the Satter Prize in Mathematics in 2011, and was elected a fellow of the AMS in 2014. Prof Wilkinson has also been very active in public outreach, giving numerous public lectures, interviews, and recently publishing an article in the New York Times.

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