UC Berkeley

We prove the abelian-nonabelian correspondence for quasimap I-functions. That is, if Z is an affine l.c.i. variety with an action by a complex reductive group G, we prove an explicit formula relating the quasimap I-functions of the GIT quotients $Z//_\theta G$ and $Z//_\theta T$ where T is a maximal torus of G. We apply the formula to compute the J-functions of some Grassmannian bundles on Grassmannian varieties and Calabi-Yau hypersurfaces in them.