Hurwitz equivalence of braid monodromies and extremal elliptic surfaces

Abstract

We discuss the equivalence between the categories of certain ribbon graphs and subgroups of the modular group Γ and use this equivalence to construct exponentially large families of not Hurwitz equivalent simple braid monodromy factorizations of the same element. As an application, we also obtain exponentially large families of topologically distinct algebraic objects such as extremal elliptic surfaces, real trigonal curves, and real elliptic surfaces. © 2011 London Mathematical Society.