Caltech/USC Algebra & Geometry Seminar

Welcome to the homepage of the joint algebra and geometry seminar at California Institute of Technology and University of Southern California! We meet biweekly on Thursday afternoons, alternating between the two campuses. Each meeting consists of two one-hour talks followed by a seminar dinner. Topics at our seminar include but are not limited to algebra, representation theory, algebraic geometry, mirror symmetry, and mathematical physics.

Below is the 2024-2025 schedule. For the academic year 2023-2024, see here.

Date Speaker Affliation Title
10/03/2024
@USC
Eugene Gorsky UC Davis
Delta Conjecture and affine Springer fibers

Abstract. Delta Conjecture of Haglund, Remmel and Wilson is the identity describing the action of Macdonald operators on elementary symmetric functions. The conjecture was proved independently by Blasiak-Haiman-Morse-Pun-Seelinger, and D'Adderio-Mellit. In this talk, I will give a geometric model for Delta conjecture using affine Springer fibers. This is a joint work with Sean Griffin and Maria Gillespie.

Harold Williams USC
Homological combinatorics of Lagrangian coamoebae

Abstract. The amoeba and coamoeba of a subvariety $Z \subset (\bC^\times)^n$ are the images under its projections to $\bR^n$ and $T^n$, respectively. In this talk we discuss joint work with Chris Kuo studying the coamoebae of Lagrangian submanifolds of $(\bC^\times)^n$, specifically how the combinatorics of their degenerations encodes the homological algebra of mirror coherent sheaves. Concretely, we associate to a free resolution $F^\bullet$ of a coherent sheaf on $(\bC^\times)^n$ a tropical Lagrangian coamoeba $T(F^\bullet)$, a certain simplicial complex in $T^n$. We show that the discrete information in $F^\bullet$ can be recovered from $T(F^\bullet)$ in common situations, and that in general there is a constructible sheaf supported on $T(F^\bullet)$ which is mirror to the coherent sheaf in the relevant sense. This sheaf can be interpreted as a singular Lagrangian brane supported on the stratified conormal bundle of $T(F^\bullet)$, and in some cases can be expressed as a degeneration of smooth Lagrangian branes. The resulting interplay between coherent sheaves on~$(\bC^\times)^n$ and simplicial complexes in $T^n$ provides a higher-dimensional generalization of the spectral theory of dimer models in~$T^2$, as well as a symplectic counterpart to the theory of brane brick models.

10/24/2024
@Caltech
Ruofan Jiang Berkeley
TBA

Abstract.

Alexei Oblomkov UMass Amherst
TBA

Abstract.

10/31/2024
@Caltech
Yong-Geun Oh IBS Geom & Phys
TBA

Abstract. The abstract

Yeqin Liu Michigan
TBA

Abstract.

11/07/2024
@USC
Irit Huq-Kuruvill Virginia Tech
TBA

Abstract. The abstract

Shaowu Zhang Caltech
TBA

Abstract. The abstract

11/21/2024
@Caltech
Burt Totaro UCLA
Endomorphisms of varieties

Abstract. A natural class of dynamical systems is obtained by iterating polynomial maps, which can be viewed as maps from projective space to itself. One can ask which other projective varieties admit endomorphisms of degree greater than 1. This seems to be an extremely restrictive property, with all known examples coming from toric varieties (such as projective space) or abelian varieties. We describe what is known in this direction, with the new ingredient being the "Bott vanishing" property. Joint work with Tatsuro Kawakami.

Xiaohan Yan Sorbonne-Université
TBA

Abstract.

12/05/2024
@USC
Thorgal Hinaul Caltech
TBA

Abstract.

TBA
TBA

Abstract. The abstract