Riemann Sphere

The Riemann sphere, also called the extended complex plane, is a one-dimensional complex manifold  (C-star) which is the one-point compactification of the complex numbers , together with two charts. (Here  denotes complex infinity.) The notation  is also used (Krantz 1999, p. 82; Lorentzen, and Waadeland 2008, p. 3).

For all points in the complex plane, the chart is the identity map from the sphere (with infinity removed) to the complex plane. For the point at infinity, the chart neighborhood is the sphere (with the origin removed), and the chart is given by sending infinity to 0 and all other points  to .

REFERENCES:

Anderson, J. W. "The Riemann Sphere ." §1.2 in Hyperbolic Geometry. New York: Springer-Verlag, pp. 7-16, 1999.

Knopp, K. Theory of Functions Parts I and II, Two Volumes Bound as One, Part I. New York: Dover, p. 4, 1996.

Krantz, S. G. "The Riemann Sphere." §6.3.3 in Handbook of Complex Variables. Boston, MA: Birkhäuser, pp. 83-84, 1999.

Lorentzen, L. and Waadeland, H. Continued Fractions, 2nd ed., Vol. 1: Convergence Theory. Amsterdam, Netherlands/Paris: Atlantis Press/World Scientific, 2008.