Time: 9:00 am, 28 November, 2025

Venue: Room 612, A6, Institute of Mathematics-VAST

Online (Join Zoom Meeting) tại link: https://zoom.us/j/99636681387?pwd=0WscBnehOJig68SqctGluVuA3RwraE.1

Abstract: Appearing in many forms and flavors, Hall algebras play an important role in representation theory. In this talk, I will describe a new version of the Hall algebra construction whose output is a (lax) braided monoidal 2-category. This construction can be thought of as a twice-categorified version of the usual Hall algebra story. The resulting object is interesting and rich already in the simplest case of the one-vertex quiver with no loop. Focusing on this example, I will explain why such an object is desirable from the perspective of categorified representation theory and low-dimensional topology. This is joint work in progress with Jonte Goedicke, Yang Hu, and Walker Stern