QM Research Seminar: Geometry and incompleteness of G2-moduli spaces

Speaker: Thibault Langlais (University of Oxford)


Abstract:

The Lie group G2 is one of the two exceptional cases in Berger's list of possible Riemannian holonomy groups. I will start by introducing the basics of G2-geometry, emphasizing its relation to Calabi-Yau geometry in (real) dimension 4 and 6. The moduli spaces of G2-manifolds are smooth and carry a natural Riemannian metric, analogous to the Weil-Petersson metric, whose properties are poorly understood. I will show that certain singular G2-manifolds correspond to finite-distance limits in the moduli spaces, which proves that G2-moduli spaces are generally not complete. Time permitting, I will also say a few words about the computation of curvatures.