Poisson Equation and Isoperimetric inequality on metric spaces Renjin Jiang Abstract: In this talk, we will talk about ioperimetric inequality and regularity of solutions to Poisson equation on metric spaces. Given a metric spaces $(X,d)$ equipped with a locally Ahlfors measure $\mu$, we show that solutions to Poisson equation enjoy Euclidean type property, provided a local 2-Poincar\'e inequality and a suitable curvature condition hold. As a result, the regularity of solutions yields a Euclidean type isoperimetric inequality.