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Department of Mathematics Seminars and Talks

 
Seminar

Graduate Student

Talk Information
Title
How to geometrically represent cohomology classes and operations
Start date and time
16:10 on Tuesday November 18, 2025
Duration in minutes
50 (until 17:00 on Tuesday November 18, 2025)
Room
BA2139
Streaming link
Streaming password
External video link
Abstract

I will begin this talk by showing how to represent the cohomology of some spaces by geometrically nice maps to spaces of cycles on spheres. These maps may be viewed as analogues of differential forms. Moreover, maps between spaces of mod p cycles represent operations on mod p cohomology that generalize the cup product, such as the Steenrod squares and Steenrod powers. These operations are fundamental to certain methods for computing stable homotopy groups, and have many other applications in algebraic topology and algebraic geometry.

I will present the first geometric construction of maps between spaces of cycles that represent mod p cohomology operations, with an eye towards applications in quantitative topology. I will draw many pictures of examples.

(arXiv:2510.12574)

Speaker Information
Full Name
Herng Yi Cheng
Personal website
Institution
University of Toronto
Institution URL