Geometry and Analysis Seminar | Mathematical Institute

Please note that the list below only shows forthcoming events, which may not include regular events that have not yet been entered for the forthcoming term. Please see the past events page for a list of all seminar series that the department has on offer.

Past events in this series

Mon, 27 Apr 2026
14:15

Gravitational instantons and Hitchin moduli spaces

Hartmut Weiss

(Universität Kiel)

Abstract

Gravitational instantons are complete 4-dimensional hyperkähler manifolds with square-integrable curvature tensor. I will address the question whether all gravitational instantons (of type ALG) can be obtained as Hitchin moduli spaces. In particular, I will explain how to compute the (hyperkähler) Torelli map for (weakly) parabolic Higgs bundles on the 4-punctured sphere. This is based on recent joint work with Fredrickson, Mazzeo and Swoboda.

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Mon, 04 May 2026
14:15

A universal Higgs bundle moduli space

Nigel Hitchin

((Mathematical Institute University of Oxford))

Abstract

The moduli space of Higgs bundles on a compact Riemann surface C for a group G is diffeomorphic to the character variety of representations

of the fundamental group in G. One description depends on the complex structure of C, the other is purely topological. Using a natural symplectic Ehresmann connection we show how to build the complex structure on the family of Higgs bundle moduli spaces over Teichmuller space and derive some consequences for the energy of the associated harmonic maps.

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Mon, 11 May 2026
14:15