The Real Projective Plane with elliptic Metric where the distance between two points and is defined as the Radian Angle between the projection of the points on the surface of a Sphere (which is tangent to the plane at a point ) from the Antipode of the tangent point.

**References**

Coxeter, H. S. M. *Introduction to Geometry, 2nd ed.* New York: Wiley, p. 94, 1969.

© 1996-9

1999-05-25