Abstract
We show that every open Riemann surface X can be obtained by glueing together a countable collection of equilateral triangles, in such a way that every vertex
belongs to finitely many triangles. Equivalently, X is a Belyi surface: There exists a holomorphic branched covering f : X → Cˆ that is branched only over −1, 1 and ∞, and with no removable singularities at the boundary of X. It follows that every Riemann surface is a branched cover of the sphere, branched only over finitely many points.
belongs to finitely many triangles. Equivalently, X is a Belyi surface: There exists a holomorphic branched covering f : X → Cˆ that is branched only over −1, 1 and ∞, and with no removable singularities at the boundary of X. It follows that every Riemann surface is a branched cover of the sphere, branched only over finitely many points.
| Original language | English |
|---|---|
| Journal | Inventiones mathematicae |
| Publication status | Accepted/In press - 18 Sept 2025 |