Schedule of Talks: Autumn 2026

Time/Location: Tuesdays 3:00-4:00pm in Smith Lab 1180


 

DATE SPEAKER TITLE HOST

September 29

Siddharth Mathur (Univ of Georgia) Formal GAGA for Brauer classes Joshua

October 13

Anand Sawant (TIFR) Weil restriction, cellular structures and Milnor-Witt K-theory Joshua

November 3

Ivan Soprunov (Cleveland State) Zeros of sparse polynomials over finite fields Joshua

November 10

Open

November 17

Deepam Patel (Purdue) TBA Joshua

November 24

Open

Abstracts

Mathur: The relationship between analytic and algebraic geometry (GAGA) is a rich area of study. For example, Grothendieck's existence theorem states that if X is proper over a complete local Noetherian ring A, then a coherent sheaf on the formal scheme X^, a priori only definable using formal power series, is actually algebraic. Such GAGA-type results are now standard tools for studying varieties and their families. One sample consequence: a compatible system of line bundles L_n on the thickenings X_n of the special fiber of X/A uniquely algebraizes to a line bundle L on X. In this talk, we answer a question Grothendieck posed in the 1960s about Brauer classes: can a Brauer class be determined from a compatible system of classes on the X_n? This is joint work with Andrew Kresch.

Sawant: The category of strictly \A^1-invariant sheaves is central to the development of \A^1-algebraic topology over a field. It is a nontrivial fact that this is an abelian, symmetric monoidal category. In this talk based on joint work with Fabien Morel, I will outline a fundamental computation in this category, namely, that of the tensor product of the Milnor-Witt K-theory sheaf with the so-called free strictly \A^1-invariant sheaf on a point, defined over a finite separable field extension of the base field. The computation is made possible by cellular \A^1-homology introduced in our earlier joint work.

Soprunov: Fix a lattice polytope P and consider the family of polynomials whose monomials have exponents in P and whose coefficients are arbitrary elements of a finite field F_q. Our goal is to estimate the maximum number of F_q-zeros of the polynomials in such a family in terms of geometric/combinatorial invariants of P. When q is large, the maximum is given by polynomials with the largest number of factors. On the combinatorial side, this corresponds to "maximal Minkowski decompositions" inside P. I will first explain this connection and review the previously known case of bivariate polynomials (i.e. dim P=2). I will then focus on the case of trivariate polynomials (i.e. dim P=3) where the combinatorics is much richer and new phenomena arise. This problem has a direct application to minimum distance estimation for a class of linear error-correcting codes, called "toric codes". The talk is based on a joint work with Kyle Meyer and Jenya Soprunova.

Patel: TBA



Schedule of Talks: Spring 2027

Time/Location TBA


 

DATE SPEAKER TITLE HOST

January 12

Open

January 19

Open

January 26

Open

February 2

Open

February 9

Open

February 16

Open

February 23

Open

March 2

Open

March 9

Open

March 16

No talk (spring break)

March 23

Open

March 30

Open

April 6

Open

April 13

Open

April 20

Open


Past Arithmetic Geometry Seminar pages

  • Arithmetic Geometry Seminar calendar from 2020-2021
  • Arithmetic Geometry Seminar calendar from 2019-2020


  • This page is maintained by Roy Joshua