New Invariants for surfaces

Abstract

We take the fundamental group of the complement of the branch curve of a generic projection induced from canonical embedding of a surface. This group is stable on connected components of moduli spaces of surfaces. Since for many classes of surfaces it is expected that the fundamental group has a polycyclic structure, we define a new invariant that comes from this structure. We compute this invariant for a few examples. Braid monodromy factorizations related to curves is a first step in computing the fundamental group of the complement of the curve, and thus we also indicate the possibility of using braid monodromy factorizations of branch curves as an invariant of a surface.