Time: 14:00-15:00, January 9, 2026

Venue: Siyuan Lecture Room, Zhihua Building, Peking University

Tea break: 15:00-15:30 at Juncai Lecture Room, Zhihua Building

Abstract: Periods are interesting numbers arising from algebraic geometry. Grothendieck’s period conjecture provides predictions on irrationality and transcendence of periods. There have been some systematic studies on certain periods, such as Baker’s theory on linear forms of logarithms of algebraic numbers. However, beyond special cases, we do not know the irrationality of simple-looking periods such as the product of two logs. In this talk, the lecturer will discuss the joint work with Calegari and Dimitrov on an irrationality result of certain product of two logs and some other periods. A classical prototype of the method was first used by Apéry to prove the irrationality of zeta(3). The key ingredient is an arithmetic holonomy theorem built upon earlier work by André, Bost, Charles (and others) on arithmetic algebraization theorems via Arakelov theory.

Lecturer profile: Tang Yunqing is a mathematician specializing in number theory and arithmetic geometry and an associate professor at the University of California, Berkeley. She was born in China and secured a BSc degree from Peking University in 2011 and then moved to Harvard University for higher education, from where she graduated with a PhD degree in 2016 under the guidance of Mark Kisin. She was awarded the SASTRA Ramanujan Prize in 2022 for "having established, by herself and in collaboration, a number of striking results on some central problems in arithmetic geometry and number theory".