Grothendieck's Dessins d'Enfants in a Web of Dualities

In this paper we show that counting Grothendieck's dessins d'enfants is universal in the sense that some other enumerative problems are either special cases or directly related to it. Such results provide concrete examples that support a proposal made in the paper to study various dualities from the point of view of group actions on the moduli space of theories. Connections to differential equations of hypergeometric type can be made transparent from this approach, suggesting a connection to mirror symmetry.