Anisotropic Wavefronts and Laguerre Geometry
  Motivated by the study of wave fronts in anisotropic media, we propose an incidence geometry of anisotropic spheres in a Finsler-Minkowski space. An anisotropic version of the Laguerre functional is considered. In some circumstances, this functional can be used to determine that two wavefronts observed at distinct times in a homogeneous, anisotropic medium, do not originate from the same source. 
Bennett Palmer
math.DG