Decorated discrete conformal equivalence in non-Euclidean geometries

Abstract

We introduce decorated piecewise hyperbolic and spherical surfaces and discuss their discrete conformal equivalence. A decoration is a choice of circle about each vertex of the surface. Our decorated surfaces are closely related to inversive distance circle packings, canonical tessellations of hyperbolic surfaces, and hyperbolic polyhedra. We prove the corresponding uniformization theorem. Furthermore, we show that on can deform continuously between decorated piecewise hyperbolic, Euclidean, and spherical surfaces sharing the same fundamental discrete conformal invariant. Therefore, there is one master theory of discrete conformal equivalence in different background geometries. Our approach is based on a variational principle, which also provides a way to compute the discrete uniformization and geometric transitions.