## –

Sara Pasquetti, CERN

Modularity of the Remodeled Open Topological String

In this talk I present a new formalism for computing unambiguously open and closed topological string amplitudes. The formalism is based on a recursive method for computing invariants of algebraic curves recently proposed by Eynard and Orantin. The resulting amplitudes are non-perturbative in both the closed and the open moduli. The computational efficiency of this formalism can be dramatically increased by rewriting the amplitudes in a form that makes their transformation properties under the modular group manifest. As an application of this method I will illustrate how to compute open Gromov-Witten invariants for the $\mathbb{C}^3/\mathbb{Z}_3$ orbifold.