## Geometry and Physics Seminar: Jim Bryan

- Date: 10/20/2014
- Time: 15:00

*UBC*

University of British Columbia

Donaldson-Thomas theory of local elliptic surfaces via the topological vertex

Donaldson-Thomas (DT) invariants of a Calabi-Yau threefold X are fundamental quantum invariants given by (weighted) Euler characteristics of the Hilbert schemes of X. We compute these invariants for the case where X is a so-called local elliptic surface --- it is the total space of the canonical line bundle over an elliptic surface. We find that the generating functions for the invariants admit a nice product structure. We introduce a new technique which allows us to use the topological vertex in this computation --- a tool which previously could only be used for toric threefolds. As a by product, we discover surprising new identities for the topological vertex. This is joint work with Martijn Kool, with an assist from Ben Young.

This is a live e-seminar hosted by The University of British Columbia in ESB 4127 and broadcast at The University of Alberta in CAB 449 at 4 pm (MDT).