TBA

Speaker: 

Bennett Cbow

Institution: 

UC San Diego

Time: 

Tuesday, June 2, 2026 - 4:00pm

Location: 

RH 306

Please note the special date and location.  This is a joint seminar with the Differential Geometry series.

RTG Distinguished Lecture Talk 1: Invitation to Geometry via Mahler's Conjectures: a mathematical opera in three acts

Speaker: 

Yanir Rubinstein

Institution: 

Maryland and Stanford

Time: 

Monday, April 13, 2026 - 4:00pm to 5:00pm

Host: 

Location: 

NS2 1201

Act I: Convexity, Duality, and Volume
Act II: Convex meets Differential
Act III: Convex meets Complex
Once convexity, duality and volume appear on stage, the Mahler
Conjectures are inevitable. These conjectures, originating in Number Theory,
predict the extremizers of the volume of a convex body times the volume of its dual.
They date from the 1930's and are still largely open. This "mathematical opera"
mostly aimed at a broad mathematical audience will attempt to recount the
over-a-century-old story of these beautiful conjectures, and their profound impact
on modern Geometric and Functional Analysis.

Adiabatic Limit and Analytic Torsion of Vector Bundles

Speaker: 

Debin Liu

Institution: 

UC Santa Barbara

Time: 

Monday, March 9, 2026 - 4:00pm

Location: 

RH 340N

Analytic torsion is a secondary topological invariant that could distinguish between closed manifolds which are homotopy equivalent but not homeomorphic. It can be defined analytically in terms of the determinant of Hodge Laplacian. In this talk, I will explain how Witten Laplacian can be used to generalize this construction to vector bundles over closed manifolds. I will also discuss how to relate the index and the analytic torsion of the total space to those of the base manifold. This is a joint work with Xianzhe Dai.

 

Wall-crossing formulae for enumerative invariants and Pandharipande-Thomas theory

Speaker: 

Reginald Anderson

Institution: 

UC Irvine

Time: 

Monday, December 8, 2025 - 4:00pm to 5:00pm

Host: 

Location: 

RH 340N

Joyce gave a framework of wall-crossing formulae for enumerative invariants in \C-linear abelian categories. We investigate implications for generating functions of Pandharipande-Thomas invariants for smooth projective Fano 3-folds. This is joint work-in-progress with Dominic Joyce.

Taut foliations, transverse flows, and Floer homology

Speaker: 

Siddhi Krishna

Institution: 

UC Berkeley

Time: 

Monday, February 9, 2026 - 4:00pm to 5:00pm

Host: 

Location: 

RH 340N

The L-space conjecture makes a prediction about which rational homology spheres can admit a taut foliation. But where could the predicted taut foliations "come from"? Must they be compatible with “natural” geometric structures on the 3-manifold? In this talk, I'll discuss forthcoming work with John Baldwin and Matt Hedden, where we address a type of geography problem for taut foliations. In particular, we show that when K is a fibered strongly quasipositive knot, large surgeries along K can never admit a taut foliation which is ‘’compatible’’ with the natural flow on the Dehn surgered manifold. I'll explain why this is surprising, and if time permits, sketch the proof. No background will be assumed — all are welcome!

Smoothly knotted surfaces in small closed 4-manifolds.

Speaker: 

Dave Auckly

Institution: 

Kansas State University

Time: 

Monday, February 2, 2026 - 4:00pm to 5:00pm

Host: 

Location: 

RH 340N

It has long been known that homeomorphic 4-manifolds may admit inequivalent smooth structures. Analogous behavior holds for embedded surfaces. Some surfaces are topologically isotopic without being smoothly isotopic. Such surfaces are said to be smoothly knotted. 

 

It turns out that it is easier to construct inequivalent smooth structures on larger 4-manifolds. Similarly, it is easier to construct closed, smoothly knotted surfaces in large 4-manifolds. 

 

In this talk, we will explain how to construct smoothly knotted surfaces in a small 4-manifold. This talk will have many pictures.

 

 

This is joint work with Konno, Mukherjee, Ruberman, and Taniguchi. 

On the genera of Quot schemes of zero dimensional quotients on curves

Speaker: 

Dragos Oprea

Institution: 

UCSD

Time: 

Monday, December 1, 2025 - 4:00pm to 5:00pm

Host: 

Location: 

RH 340N

We study Quot schemes of rank 0 quotients on smooth projective curves. These Quot schemes exhibit a rich and highly structured geometry, with formal parallels to the Hilbert schemes of points on surfaces.

In this talk, we first note formulas for the twisted \chi_y-genera with values in tautological line bundles pulled back from the symmetric product via the Quot-to-Chow morphism, and for the associated twisted Hodge numbers. Going further, we give formulas for the level 2 (twisted) elliptic genus for quotients of a vector bundle of even rank. We also discuss the case of level \ell elliptic genera, for higher values of \ell. 

Equivariant algebraic K-theory of G-manifolds

Speaker: 

Mona Merling

Institution: 

UPenn

Time: 

Monday, November 3, 2025 - 4:00pm to 5:00pm

Host: 

Location: 

RH 340N

Algebraic K-theory of smooth compact manifolds provides a homotopical lift of the classical h-cobordism theorem and serves as a critical link in the chain of homotopy theoretic constructions that show up in the classification of manifolds and their diffeomorphisms. I will give an overview of this story and recent progress on an equivariant homotopical lift of the h-cobordism theorem developed in joint work with Goodwillie, Igusa, and Malkiewich. 

The large time behavior of the heat kernel on homogenous spaces and Bismut's formula

Speaker: 

Xiang Tang

Institution: 

Washington University in St. Louis

Time: 

Monday, November 24, 2025 - 4:00pm

Location: 

RH 340N

Let G be a connected linear real reductive group with a maximal compact subgroup K. In this talk, we will discuss an approach to studying the large-time behavior of the heat kernel on the corresponding homogeneous space G/K using Bismut's formula. We will try to explain how Bismut's formula provides a natural link between the index theory and representation theory.  In particular, Vogan's λ-map in the representation theory of G plays a central role in the large time asymptotic analysis about the trace of the heat kernel. This talk is based on joint works with Shu Shen and Yanli Song. 

Seeing Space(time)

Speaker: 

Steve Trettel

Institution: 

University of San Francisco

Time: 

Thursday, May 15, 2025 - 2:15pm to 3:05pm

Host: 

Location: 

ISEB 1200

For two thousand years geometry was synonymous with the perfectly flat expanse imagined by Euclid. But nineteenth‑century investigations into the parallel postulate lifted a veil from our eyes, revealing the richer realms charted by Gauss and Riemann. In this talk we’ll take an “insider’s tour” of those curved landscapes.

We begin by thinking carefully about what it means to see, and use this to step inside new geometries, by tracing light rays along their geodesics. Modern computing affords us the ability to make this thought experiment a reality, with interactive ray-traced demos and experiments.  Using these, we will explore curved spaces important to modern mathematics, and physics, including the curved spacetime we live in.

 

 

 

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