Time：14:00-17:00, Friday, August 1 2025
Venue：E4-233
Host：Jiyuan Han, ITS
Speaker：Mingyang Li, UC Berkeley
Title：Gravitational instantons and harmonic maps
Abstract：It is known from general relativity that axisymmetric stationary black holes can be reduced to axisymmetric harmonic maps into the hyperbolic plane H^2, while in the Riemannian setting, 4d Ricci-flat metrics with torus symmetry can also be locally redcued to such harmonic maps satisfying a tameness condition. We study such harmonic maps and application includes a construction of infinite many new complete, asymptotically flat, Ricci-flat 4-manifolds with arbitrarily large b_2. Joint work with Song Sun.
