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Ph.D and M.Sc Defences

Monday, August 12, 2024

Time: 9:30am

Student: ZHOU, YICHEN

Supervisor: MSC S YUKSEL & Y SONG

Title: Robustness to Model Approximation and Learning in Wasserstein Regular MDPs

Number Theory Seminar

Wednesday, May 15th, 2024

Time: 3:30 p.m.  Place: Jeffery Hall, Room 222

Speaker: Anup Dixit (IMSc)

Title: Lower bounds on Weil height for certain infinite non-Galois extensions

Abstract: For a non-zero algebraic number $\alpha$, let $h(\alpha)$ denote its logarithmic Weil height. A classical theorem of Kronecker asserts that $h(\alpha)=0$ if and only if $\alpha$ is a root of unity. For $\alpha$ not a root of unity, it is an important theme to understand lower bounds for $h(\alpha)$. In 2002, Bombieri and Zannier obtained explicit lower bounds on certain infinite Galois extensions in terms of their local degrees. In this talk, we formulate and prove an analogous result for infinite non-Galois extensions. This is joint work with Sushant Kala.

Number Theory Seminar

Wednesday, May 15th, 2024

Time: 2:30 p.m.  Place: Jeffery Hall, Room 222

Speaker: Siddhi Pathak (CMI)

Title: On the zeros of variants of Ramanujan polynomials

Abstract: In 2011, M. R. Murty, C. Smyth and R. Wang introduced the family of 'Ramanujan polynomials' and proved that the non-real zeros of all such polynomials lie on the unit circle. These polynomials are related to the period polynomial of standard Eisenstein series. Since then, it has been established that period polynomials associated to generalized Eisenstein series and Hecke newforms also have all their roots on the unit circle. In this talk, we discuss recent results regarding the unimodularity of zeros of certain cognate polynomials.

Number Theory Seminar

Wednesday, May 8th, 2024

Time: 2:30 p.m.  Place: Jeffery Hall, Room 222

Speaker: Nic Fellini (Queen's University)

Title: The distribution of k-full numbers

Abstract: A positive integer n is called k-full if for each prime divisor p of n, p^k divides n. We will explore some questions related to the distribution of k-full numbers and some variations on these questions.

PDEs & Applications Seminar

Tuesday, April 9th, 2024

Time: 9:30 a.m.  Place: Jeffery Hall, Room 319 (Via Zoom)

Speaker: Mark Veraar (Delft University of Technology)

Title: Stochastic partial differential equations in critical spaces

Abstract: In this talk I will give an overview of several recent developments on quasi- and semi-linear stochastic PDEs in critical spaces. I will present a new method to prove local and global well-posedness results, and new bootstrap method to show higher order regularity of the solution. In the talk several applications to reaction diffusion equations will be discussed in details. In particular, the new setting allows to prove global well-posedness for several systems which do not satisfy classical coercivity estimates. The talk is based on joint work with Antonio Agresti.

Curves Seminar

Thursday, April 4th, 2024

Time: 4:00 p.m.  Place: Jeffery Hall, Room 319

Speaker: Luke Steverango

Title: Defining Cluster Algebras by Generators and Relations

Abstract: A traditional way to describe a commutative algebra over a ring is as a quotient of a polynomial ring. One would hope to get an analogous way of describing cluster algebras in a similar way. Unfortunately, that runs into two issues. These issues are that the set of cluster variables is typically infinite and the exchange relations do not, in general, generate the ideal of all relations among cluster variables. We explore each of these issues, with particular emphasis on the second issue.

Math & Stats Department Colloquium (3MT Competition)

Friday, April 5th, 2024

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

Speaker(s): Jerin Farin (Giusy Mazzone)
Nic Fellini (Ram Murty)
Annika Fuernsinn (Bahman Gharesifard)
Skye Griffith (Glen Takahara and Wes Burr (Trent))
Neil MacVicar (Francesco Cellarosi and Jamie Mingo)
Richard Zhao (Felicia Magpantay)
Sasha Zotine (Mike Roth and Greg Smith)

Details: The Department of Mathematics and Statistics will once again host its own 3 Minute Thesis Competition. Seven graduate students will explain some aspect of their research in just three minutes following the official 3MT rules copied below. The winners will be selected by secret ballot following the judging criteria also copied below. All department members –graduate students, faculty, postdocs and staff - who attend the entire event and listen to all 7 presentations will be able to cast one ballot selecting their top 3 choices, and the winners will be announced in the 5th floor lounge immediately after the competition.