강연자: Yehao Zhou

소속: Shanghai Institute for Mathematics and Interdisciplinary Sciences (SIMIS)

장소: 서울대학교 129동 406호

시간:

2026-04-14(화) 10:00~11:30

2026-04-14(화) 14:00~15:30

2026-04-16(목) 10:00~11:30

Lecture 1: Maulik-Okounkov’s stable envelope theory

Abstract: In this lecture we discuss the construction of stable envelopes and R-matrices on the equivariant cohomologies of symplectic varieties. General theory will be illustrated by explicit computations in simple examples including cotangent bundles of Grassmannians.

Lecture 2: Symmetric GIT quotient and critical stable envelopes

Abstract: We start with an example of non-symplectic variety, the resolved conifold, and show that the definition of stable envelopes can actually be extended to a large class of varieties: the symmetric GIT quotient. We will explain the idea of proof of the existence and uniques of stable envelopes for symmetric GIT quotient. And we will also explain how the construction can be further extended to critical cohomologies.

Lecture 3: Relation to COHA and application to the study of (shifted) Yangians

Abstract: We will focus on the symmetric quiver varieties in this lecture, and explain the relation between critical stable envelopes and framed critical cohomological Hall algebras (COHA). Using COHA, we introduce Hall envelopes and use them to construct R-matrices for (shifted) Yangians.

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