Algebra Seminar
(Mon 3:30-4:30pm, Kap 265)

Organizer: Cris Negron

Topics include (but are not limited to):

Algebra, representation theory, algebraic and arithmetic geometry, homotopy theory, and mathematical physics.

Spring 2026

Date Location Speaker Abstract
Jan 19 Holiday
Jan 26 Organizer away
Feb 2
Wed. Feb 11, 2pm Biman Roy (USC) Geometric implications of 𝔸1-connectedness

Abstract: 𝔸1-homotopy theory, introduced by Morel and Voevodsky, allows us to apply the algebraic topology techniques in algebraic geometry. From the standpoint of homotopy theory of a model category, there is an abstract notion of 𝔸1-connected component sheaf of a variety. It is a natural goal to understand the 𝔸1-connected component sheaf of a variety geometrically and this was initiated by Asok and Morel. They proved that a smooth proper variety X over a field k is 𝔸1-connected if and only if for every finitely generated separable field extension F/k, any two F-points in X can be joined by a chain of 𝔸1F’s in X. In this talk, we will see that if X is an 𝔸1-connected smooth variety over an algebraically closed field k, then X is 𝔸1-uniruled. Thus in particular, if k is of characteristic zero, then X has negative logarithmic Kodaira dimension. We will also see some useful consequences of this result. This is based on my Ph.D. thesis and this is a joint work with Utsav Choudhury.
Feb 16 Holiday
Feb 23 Nathan Benjamin (USC) [Moved to Mar 23]
March 2 Haoyang Liu (UCSB) [Moved to Apr 27]
March 9 Mark Ebert (UCLA)
March 16 Off
March 23 Nathan Benjamin (USC) Conformal field theory: from magnets to Hodge numbers

Abstract: I will introduce the notion of a conformal field theory (CFT), which are quantum field theories at the endpoints of renormalization group flows. CFTs show up in many areas of physics, including second-order phase transitions, string worldsheet theories, and quantum gravity in anti de Sitter space. CFTs also have applications in pure math, and can be thought of as a kind of "generalization" of geometric objects. As an example, I will show how topological invariants of certain manifolds (such as Hodge numbers) are in one-to-one correspondence with a special class of quantum states in a 2d CFT.
March 30 Enrico Lampetti (Sorbonne U)
April 6
April 13
April 20
April 27 Haoyang Liu (UCSB)

Previous semester

Mailing list: Contact me if you want to be added to the seminar mailing list.

See our friends at the Geometry seminar (M 2:00 pm) and the Combinatorics seminar (W 2:00 pm).