Editing Homogeneous coordinates (section)

==Other projective spaces==
The use of [[real number]]s gives homogeneous coordinates of points in the classical case of the real projective spaces, however any [[field (mathematics)|field]] may be used, in particular, the [[complex number]]s may be used for [[complex projective space]]. For example, the [[complex projective line]] uses two homogeneous complex coordinates and is known as the [[Riemann sphere]]. Other fields, including [[finite field]]s, can be used.

Homogeneous coordinates for projective spaces can also be created with elements from a [[division ring]] (a skew field). However, in this case, care must be taken to account for the fact that multiplication may not be [[Commutative property|commutative]].<ref>{{harvnb|Garner|1981|pp=32&ndash;33}}</ref>

For the general [[ring (mathematics)|ring]] ''A'', a [[projective line over a ring|projective line over ''A'']] can be defined with homogeneous factors acting on the left and the [[projective linear group]] acting on the right.