“…In the context of projective geometry, earlier similar ideas are due to Plücker [49] and Klein [40]. The idea of Voronoȋ has been applied successfully to refinements of Voronoȋ's criterion (see [5,73,30]), lattice coverings with balls of extreme density (see [4,14,64,32]), minima of the Epstein zeta function (see [16,52,12,57,31]), geodesics on Riemannian manifolds of a Teichmüller space (see [59][60][61][62]), and John type and minimum position problems (see [23,27,35,33]). …”