# Seminars and colloquia

E.g., Sep. 25, 2022

### Jim Bryan

UBC
A theory of Gopakumar-Vafa invariants for orbifold Calabi-Yau threefolds

September 26, 2022

We define integer valued invariants of an orbifold Calabi-Yau threefold $X$ with transverse ADE orbifold points. These invariants contain equivalent information to the Gromov-Witten invariants of $X$ and are related by a Gopakumar-Vafa like formula which may be regarded as a ... Read more
• Intercontinental Moduli and Algebraic Geometry Seminar

### Woonam Lim

ETH Zürich
Virasoro constraints in sheaf theory and vertex algebras

October 3, 2022

In enumerative geometry, Virasoro constraints first appeared in the context of moduli of stable curves and maps. These constraints provide a rich set of conjectural relations among Gromov-Witten descendent invariants. Recently, the analogous constraints were formulated in ... Read more
• Intercontinental Moduli and Algebraic Geometry Seminar

### Dhruv Ranganathan

Cambridge University
Ranganathan Lecture Title

October 24, 2022