On the vertex functions of type A quiver varieties

The goal of this paper is to better understand the quasimap vertex functions of type $A$ Nakajima quiver varieties. To that end, we construct an explicit embedding of any type $A$ quiver variety into a type $A$ quiver variety with all framings at the rightmost vertex of the quiver. Then we consider quasimap counts, showing that the map induced by this embedding on equivariant $K$-theory preserves vertex functions.