The 4D/2D correspondence recently discovered by Beem et al. constructs representation theoretical objects, such as representations of affine Kac-Moody algebras, as invariants of 4 dimensional superconformal field theories with N = 2 supersymmetry. Furthermore, it is expected that there is a remarkable duality between the representation theoretical objects constructed in this way and the geometric invariants called Higgs branch of the original 4 dimensional theory.In this talk, I will discuss about this duality from a mathematical perspective.