2 papers
math.AG2025
Topological groupoids with involution and real algebraic stacks
Emiliano Ambrosi, Olivier de Gaay Fortman
To a topological groupoid endowed with an involution, we associate a topological groupoid of fixed points, generalizing the fixed-point subspace of a topological space with involut…
math.AG2021
Hyperbolic geometry and real moduli of five points on the line
Olivier de Gaay Fortman
We show that each connected component of the moduli space of smooth real binary quintics is isomorphic to an open subset of an arithmetic quotient of the real hyperbolic plane. Mor…