PhD Candidate: Ali Cheraghi

Supervisor: Jacob Tsimerman

Thesis title: Special Correspondences of Abelian Varieties and Eisenstein Series

****

****

A draft of the thesis can be found here: thesis

May

16

PhD Candidate: Ali Cheraghi

Supervisor: Jacob Tsimerman

Thesis title: Special Correspondences of Abelian Varieties and Eisenstein Series

****

****

A draft of the thesis can be found here: thesis

May

16

Tuesday, July 19, 2022 at 12:00 p.m.

PhD Candidate: Georgios Papas

Supervisor: Jacob Tsimerman

Thesis title:

Some topics in the arithmetic of Hodge structures and an Ax-Scanuel theorem for GLn

****

****

A draft of the thesis can be found here: G.Papas, Thesis

Apr

21

Wednesday, June 29, 2022 at 10:00 a.m.

PhD Candidate: Carrie Clark

Supervisor: Almut Burchard

Thesis title: :

****

****

A draft of the thesis can be found here:

Apr

21

Friday, June 17, 2022 at 3:00 p.m. (sharp)

PhD Candidate: Jeffrey Im

Supervisor: George Elliott

Thesis title: : Coloured Isomorphism of Classifiable C*-algebras

****

It is shown that the coloured isomorphism class of a unital, simple, Z-stable, separable amenable C∗-algebra satisfying the Universal Coefficient Theorem (UCT) is determined by its tracial simplex. This is a joint work with George A. Elliott.

****

A draft of the thesis can be found here: thesis

Apr

21

PhD Candidate: Assaf Bar-Natan

Supervisor: Kasra Rafi

Thesis title: Geodesic Envelopes in Teichmuller Space Equipped with the Thurston Metric

****

****

A draft of the thesis can be found here:

Apr

21

Thursday, June 23, 2022 at 10:00 a.m. (sharp)

PhD Candidate: Stefan Dawydiak

Supervisor: Alexander Braverman

Thesis title: Three pictures of Lusztig’s asymptotic Hecke algebra

****

****

A draft of the thesis can be found here:

Apr

21

Wednesday, June 1, 2022 at 11:00 a.m. (sharp)

PhD Candidate: Kenneth Chiu

Supervisor: Jacob Tsimerman

Thesis title: Functional transcendence in mixed Hodge theory

*****

Ax-Schanuel theorem is a function field analogue of the Schanuel’s conjecture in transcendental number theory. Building on the works of Bakker, Gao, Klingler, Mok, Pila, Tsimerman, Ullmo and Yafaev, we extend the Ax-Schanuel theorem to mixed period mappings. Using this together with the Ax-Schanuel theorem for foliated principal bundles by Blázquez-Sanz, Casale, Freitag, and Nagloo, we further extend the Ax-Schanuel theorem to the derivatives of mixed period mappings. The linear subspaces in the Ax-Schanuel theorem are replaced by weak Mumford-Tate domains, which are certain group orbits of mixed Hodge structures. In particular, we prove that these domains have complex structures, and that their real-split retractions can be decomposed into semisimple and unipotent parts. We prove that the image of a mixed period mapping is contained in the weak Mumford-Tate domain that arises from the monodromy group of the variation. O-minimal geometry, namely the definable Chow theorem and the Pila-Wilkie counting theorem, are used in the proof of our extension of the Ax-Schanuel theorem.

****

The draft of the thesis can be found here:Thesis

Mar

14

Tuesday, April 12, 2022 at 11:00 a.m. (sharp)

PhD Candidate: Joshua Lackman

Supervisor: Marco Gualtieri

Thesis title: The van Est Map on Geometric Stacks

***

We generalize the van Est map and isomorphism theorem in three ways. First, we generalize the van Est map from a comparison map between Lie groupoid cohomology and Lie algebroid cohomology to a (more conceptual) comparison map between the cohomology of a stack $\mathcal{G}$ and the foliated cohomology of a stack $\mathcal{H}\to\mathcal{G}$ mapping into it. At the level of Lie grouoids, this amounts to describing the van Est map as a map from Lie groupoid cohomology to the cohomology of a particular LA-groupoid. We do this by, essentially, associating to any

(nice enough) homomorphism of Lie groupoids $f:H\to G$ a natural foliation

of the stack $[H^0/H]\,.$ In the case of a wide subgroupoid $H\xhookrightarrow{}G\,,$ this foliation can be thought of as equipping

the normal bundle of $H$ with the structure of an LA-groupoid. This generalization allows us to derive results that couldn’t be obtained with the usual van Est map for Lie groupoids. In particular, we recover classical results, including van Est’s isomorphism theorem about the maximal compact subgroup, which we generalize to proper subgroupoids, as well as the Poincar\'{e} lemma. Secondly, we generalize the functions that we can take cohomology of in the context of the van Est map; instead of using functions valued in representations, we can use functions valued in modules — for example, we can use $S^1$-valued functions and $\mathbb{Z}$-valued functions. This allows us to obtain classical results about linearizing group actions, as well as results about lifting group actions to gerbes. Finally, everything we do works in the holomorphic category in addition to the smooth category.

***

The draft of the thesis can be found here: Thesis Draft March 21

Feb

25

Tuesday, April 5, 2022 at 2:00 p.m. (sharp)

PhD Candidate: Saied Sorkhou

Supervisor: Joe Repka

Thesis title: Levi Decomposable Subalgebras of Classical Lie Algebras with Regular

Simple Levi Factor

***

This thesis describes and characterizes a significant class of subalgebras of the classical Lie algebras, namely those which are Levi decomposable with regular and simple Levi factor, with select exceptions. Such subalgebras are entirely determined by their Levi factors and radicals. The possible Levi factors are well-established in the literature and so the contribution of this thesis is a characterization of the radicals. The radicals naturally decompose into nontrivial and trivial components. The nontrivial component is found to be fully classified by subsets of the parent root system and Weyl group. However, a classification of the trivial component requires solving the open problem of classifying solvable subalgebras of classical Lie algebras. Nonetheless, this thesis establishes a criterion on the trivial components for determining when two such subalgebras are conjugate. This thesis also briefly explores the ramifications of relaxing

simplicity of the Levi factor to allow for semisimplicity.

***

A draft of the thesis is available here: thesis_draft_Feb_23_2022

Feb

25

Everyone is welcome to attend the presentation. *Refreshments will be served in the lounge at 1:30 p.m.!*

Wednesday, April 6, 2022 at 2:00 p.m.

PhD Candidate: Malors Espinosa Lara

Supervisor: Jim Arthur

Thesis title: Explorations on Beyond Endoscopy

***

In this thesis we provide a description of the first paper on Beyond Endoscopy by Altu˘g and explain how to generalize to totally real fields, based on a joint work of the author with Melissa Emory, Debanjana Kundu and Tian An Wong, and is a work in preparation. This part is mostly expository, and we refer the reader to the relevant paper [7] Furthermore, we prove a conjecture of Arthur. In his original paper on Beyond

Endoscopy, Langlands provides a formula for certain product of orbital integrals in GL(2, Q), subsequently used by Altu˘g to manipulate the regular elliptic part of the trace formula with the goal of isolating the contribution of the trivial representation. Arthur predicts this formula should coincide with a product of polynomials associated to zeta functions of orders constructed by Zhiwei Yun. We prove this is the case by finding the explicit polynomials and recovering the original formula from them.

We also explain how some aspects of the strategy used can be interpreted as problems of independent interest and importance of their own.

***

A draft of the thesis is available here: Malors_Espinosa_PhD_Thesis_8FEB2022