From Encyclopediaofmath The length of the shortest geodesic line connecting two points (or two sets). In variational calculus the geodesic distance is the extremal value of the functional under study concerning extremals connecting the two points.
| [a1] | H. Busemann, "The geometry of geodesics" , Acad. Press (1955) |
| [a2] | W. Klingenberg, "Riemannian geometry" , de Gruyter (1982) (Translated from German) |