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.


Winter 2021 Grad Colloquium Thursdays
talk @ 4pm, "tea" @ 3:30pm, 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)

1/21 Andrew Kobin UCSC
1/28 hold for other event
2/4 hold for other event
2/11 hold for other event
2/18 hold for other event
2/25 TBD
3/4 Ezekiel Lemann SUNY Binghamton

Thursday, January 21, 2021

Andrew Kobin, UCSC

What is a stack?

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.

Thursday, March 4, 2021

Ezekiel Lemann, SUNY Binghamton