**Speaker:** Tom Bridgeland (University of Sheffield)

**Title:** Donaldson-Thomas invariants and hyperkahler manifolds: the example of theories of class S[A1]**Abstract:** I will report on a project which aims to encode the DT invariants of a CY3 triangulated category in a geometric structure on its stability space. I will focus on a class of categories whose stability spaces were studied in previous joint work with Ivan Smith, and which correspond in physics to theories of class S[A1]. I will describe the resulting geometric structures using a kind of complexified Hitchin system parameterising bundles on curves equipped with pencils of flat connections.