The extended complex plane is the name given to the complex plane with a point at infinity attached:
,
where 
denotes complex infinity. It is also called the
Riemann sphere and is various denoted 
or 
.
Extended Complex Plane
See also
C-*, Complex Infinity, Complex Plane, Riemann SphereExplore with Wolfram|Alpha
References
Krantz, S. G. "The Topology of the Extended Complex Plane." §6.3.2 in Handbook of Complex Variables. Boston, MA: Birkhäuser, p. 83, 1999.Referenced on Wolfram|Alpha
Extended Complex PlaneCite this as:
Weisstein, Eric W. "Extended Complex Plane." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/ExtendedComplexPlane.html