A four-term exact sequence of fundamental groups of orbit configuration spaces

Abstract

We deduce that the fundamental groups of the orbit configuration spaces of an effective and properly discontinuous action of a discrete group on a connected aspherical 2-manifold, with isolated fixed points, fit into a four-term exact sequence. This comes as a consequence of the four-term exact sequence of orbifold pure braid groups ([18], [11] and [19]). The proof relates these two exact sequences and also draws a new consequence (Corollary 2.3) on the later one.