Two points
on a compact Riemann surface such that lies on every geodesic passing
through ,
and conversely. An oriented surface where every point belongs to a Wiedersehen pair
is called a Wiedersehen surface.
The name is the German word for "seeing again" and was introduced by Blaschke.
Blaschke, W. Vorlesung über Differentialgeometrie I. Berlin: Springer-Verlag, 1921.Klingenberg, W. Course
in Differential Geometry. New York: Springer-Verlag, p. 164, 1978.
on a compact Riemann surface such that 
lies on every geodesic passing
through 
,
and conversely. An oriented surface where every point belongs to a Wiedersehen pair
is called a Wiedersehen surface.
