3d expansions of 5d instanton partition functions

We propose a set of novel expansions of Nekrasov's instanton partition functions. Focusing on 5d supersymmetric pure Yang-Mills theory with unitary gauge group on C-q,t(2) 1 x S-1, we show that the instanton partition function admits expansions in terms of partition functions of unitary gauge theories living on the 3d subspaces C-q x S-1, Ct-1 x S-1 and their intersection along S-1. These new expansions are natural from the BPS/CFT viewpoint, as they can be matched with W-q,W-t correlators involving an arbitrary number of screening charges of two kinds. Our constructions generalize and interpolate existing results in the literature