Computing shortest homotopic cycles on polyhedral surfaces with hyperbolic uniformization metric

The problem of computing shortest homotopic cycles on a surface has various applications in computational geometry and graphics. In general, shortest homotopic cycles are not unique, and local shortening algorithms can become stuck in local minima. For surfaces with a negative Euler characteristic that can be given a hyperbolic uniformization metric, however, we show that they are unique and can be found by a simple locally shortening algorithm. We also demonstrate two applications: constructing extremal quasiconformal mappings between surfaces with the same topology, which minimize angular distortion, and detecting homotopy between two paths or cycles on a surface.

► We consider the classical problem of computing shortest homotopic cycles on surfaces.
► Shortest homotopic cycles are unique for surfaces with hyperbolic metric.
► We apply a simple locally shortening algorithm to compute shortest homotopic cycles.
► We apply for constructing extremal quasiconformal mappings between surfaces.
► We apply for homotopy detection of paths or cycles on surfaces.