Graduate Colloquium

The graduate students of the Mathematics Department coordinate a quarterly colloquium. The talks are generally every Thursday from 4-5 PM, with an informal tea (get-together) beforehand.


Spring 2021 Grad Colloquium Thursdays
"tea" @ ~3:30pm, talk @ 4pm, California Time
Meeting ID: 946 8725 0529 -- Passcode: 674336 -- Direct link
For further information please contact
Deewang Bhamidipati (
or David Rubinstein (

Schedule (click dates for title and abstract)

4/8 Andrew Kobin What is a stack ? (part 2)
4/15 Sandra Nair So what is a Shimura Curve?
4/22 Herman Yu tbd
4/29 Philip Barron tbd
5/6 Justin Lake tbd
5/13 Yufei Shan tbd
5/20 Malachi Alexander tbd
5/27 John McHugh tbd

Thursday, April 8, 2021

Special Time: "pre-talk" review of part 1 from 3:30 - 4 PM; talk starts at 4 PM

Andrew Kobin, UCSC

What is a stack? (part 2)

Many classification problems in math are made harder by nontrivial automorphisms of the objects one is trying to classify. Groupoids, and ultimately stacks, are the right language to solve these problems in a satisfying way. In this talk, I will gently ease the audience into the waters of algebraic geometry while sprinkling in the motivating principles behind stacks. Then we will look at some important examples of algebraic stacks, including quotient stacks and the moduli stack of elliptic curves. The talk will be preceded by a "pre-talk" where key facts and ideas from the first part of this talk, that took place last quarter, will be recalled.

Thursday, April 15, 2021

Sandra Nair, University of Michigan

So what is a Shimura Curve?

Shimura varieties are one of the objects needed to realize the ambitious Langlands’ correspondence. They are infamous for being rather technical. Historically, their one-dimensional avatar, called Shimura curves, were studied first, in the context of class field theory. In this talk, we will build up to a working definition of what a Shimura curve is, using classical modular curves as our Ariadne’s Thread.

22nd April
Speaker: Herman Yu (UC Santa Cruz)
Title: TBD
Abstract: TBD

29th April
Speaker: Philip Barron (UC Santa Cruz)
Title: TBD
Abstract: TBD

6th May
Speaker: Justin Lake (UC Santa Cruz)
Title: TBD
Abstract: TBD

13th May
Speaker: Yufei Shan (UC Santa Cruz)
Title: TBD
Abstract: TBD

20th May
Speaker: Malachi Alexander (UC Santa Cruz)
Title: TBD
Abstract: TBD

27th May
Speaker: John McHugh (UC Santa Cruz)
Title: TBD
Abstract: TBD