Date
Tuesday April 11, 2023Location
Jeffery Hall, Room 222Tuesday, April 11th, 2023
Time: 1:00 p.m. Place: Jeffery Hall, Room 222
Speaker: Rita Fioresi (University of Bologna)
Title: On generalized root systems
Abstract:
Website details here: https://mast.queensu.ca/~georep/Fall%20'22.html
Date
Thursday March 30, 2023Location
Jeffery Hall, Room 118Thursday, March 30th, 2023
Time: 5:30 p.m. Place: Jeffery Hall, Room 118
Speaker: Greg Smith (Queen's University)
Title: How to win a Field’s Medal?
Abstract: Why was June Huh awarded a Fields Medal in 2022?
In this talk, we will probe some connections between combinatorics and algebraic geometry. We hope to provide an understanding of the Dowling-Wilson conjecture and some insight into its proof.
Date
Wednesday March 29, 2023Location
Jeffery Hall, Room 222 & ZoomWednesday, March 29th, 2023
Time: 1:00 p.m. Place: Jeffery Hall, Room 222 & Zoom
Speaker: Sonja Ruzic
Title: Orbit-Cone Correspondence
Abstract: For a toric variety V with torus T, we will look at an example to see how the normal fan of V is related to the T-orbits in V. Then we will formalize these ideas via the Orbit-Cone Correspondence theorem.
Date
Monday April 3, 2023Location
Jeffery Hall, Room 222Monday, April 3rd, 2023
Time: 4:30 p.m. Place: Jeffery Hall, Room 222
Speaker: Greg Smith (ºÚÁϳԹÏ×ÊÔ´)
Title: Cohomology of toric vector bundles
Abstract:
Website details here: https://mast.queensu.ca/~georep/Fall%20'22.html
Date
Friday March 31, 2023Location
Jeffery Hall, Room 234Friday, March 31st, 2023
Time: 2:30 p.m. Place: Jeffery Hall, Room 234
Speaker: Hanna Jankowski (York University)
Title: Some results for the Isotonic Single Index model
Abstract: The semiparametric single index model is a popular dimension reduction tool used in a variety of applications. It can be viewed as a further generalization of generalized linear models, where the link function is not specified. In this talk, I will discuss the isotonic version of the nonparametric single index model, where the link function is assumed to be increasing. A key benefit of the assumption is that this approach is free of any additional tuning parameters, such as the bandwidth. Furthermore, nearly all parametric generalized index models have increasing link functions, making it a very natural assumption. In this talk, I will discuss estimation, computation, as well as rates of convergence under different underlying assumptions for the isotonic index model. This is joint work with Fadoua Balabdaoui from ETH Zurich and Cecile Durot from Paris X Nanterre.
Date
Monday March 27, 2023Location
Jeffery Hall, Room 319Monday, March 27th, 2023
Time: 4:30 p.m. Place: Jeffery Hall, Room 319
Speaker: Dominic Austria (Queen's University)
Title: Congruent Numbers and Tunnell’s Theorem
Abstract: We will discuss congruent numbers, their relation to elliptic curves, and some known results about the congruent number problem. The focus will be on outlining the proof of Tunnell’s theorem. We discuss the key tools needed for this--the L-function of a particular elliptic curve associated with the congruent number problem, and modular forms, of both integer weight and half integer weight. We will then see how results on both of these topics can be combined, using the theorems of Shimura and Waldspurger, to classify the congruent numbers up to conjecture.
Date
Wednesday March 22, 2023Location
Jeffery Hall, Room 234Wednesday, March 22nd, 2023
Time: 12:00 p.m. Place: Jeffery Hall, Room 234
Speaker: Elizabeth Collins-Woodfin (McGill)
Title: Phase transitions in spherical spin glass models
Abstract: This talk will focus on a series of recent results involving phase transitions in the spherical Sherrington-Kirkpatrick (SSK) spin glass model. In addition to their physical meaning, these phase transitions can be interpreted in the context of statistics, random matrix theory, and optimization problems. In the first half of the talk, I will discuss the transition between SSK with an external field and SSK without an external field (based on my joint work with Baik, le Doussal, Wu). In the second half of the talk, I will discuss the transition between high and low temperature SSK. Recent papers by Landon and by Johnstone-Klochkov-Onatski-Pavlyshyn have analyzed the free energy fluctuations of SSK at the critical temperature. I will summarize these papers and then discuss my current work to extend their result to a bipartite spin glass model (joint with Le). While the context for all of these works is spin glass, my focus is primarily theoretical and draws on tools from random matrix theory, as well as contour integral analysis.
Date
Wednesday March 22, 2023Location
Jeffery Hall, Room 222 & ZoomWednesday, March 22nd, 2023
Time: 1:00 p.m. Place: Jeffery Hall, Room 222 & Zoom
Speaker: Alexandre (Sasha) Zotine
Title: Toric Variety of a Fan
Abstract: We'll see how we can glue affine varieties coming from the cones of a fan to construct a toric variety.
Date
Monday March 27, 2023Location
Jeffery Hall, Room 222Tuesday, March 27th, 2023
Time: 4:30 p.m. Place: Jeffery Hall, Room 222
Speaker: David Wehlau (RMC & ºÚÁϳԹÏ×ÊÔ´)
Title: Rings of invariants of Finite Classical Groups
Abstract:
Website details here: https://mast.queensu.ca/~georep/Fall%20'22.html
Date
Thursday March 23, 2023Location
Jeffery Hall, Room 118Thursday, March 23rd, 2023
Time: 5:30 p.m. Place: Jeffery Hall, Room 118
Speaker: Teresa Chiri (Queen's University)
Title: Dido's Problem: from the foundation of Carthage to the eradication of plant diseases
Abstract: In this talk we will trace the isoperimetric problem from Queen Dido to some recent applications. We will discover why we need to study the calculus of variations to construct a larger town, to create more sophisticated materials, and to fight plant diseases
