Abstract:
I will revisit the Seiberg-Witten description of the Coulomb branch of rank-one 4d N=2 supersymmetric QFTs, including aspects of the global symmetry, from the point of view of rational elliptic surfaces. This will include, in particular, a detailed study of the 5d superconformal field theories with E_n symmetry, compactified on a circle. I will also sketch how to derive BPS quivers from that perspective. Interesting modular properties of the SW geometries will play a key role.