On derived commutative rings

Seminar: 
Arithmetic Algebraic Geometry
Event time: 
Monday, October 26, 2026 - 4:30pm to 6:00pm
Location: 
KT 801
Speaker: 
Arpon Raksit
Speaker affiliation: 
Northwestern University
Event description: 

Here “derived commutative ring” refers to a nonconnective generalization of animated commutative rings,

first defined by Mathew; in other words, it’s a common home for the homotopy theories of simplicial and cosimplicial

commutative rings. I first encountered the notion while studying Hochschild homology and de Rham cohomology.

In this talk, I’ll describe a different presentation of the category. It’s an instance of a fairly simple and very general pattern,

of which there are other interesting instances too. I plan to also discuss one more, a notion of “synthetic E-infinity ring”,

and the relevance of this to the study of topological Hochschild homology and prismatic cohomology (this part will be

based on joint work with Devalapurkar, Hahn, and Senger).