Complex projective plane

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In mathematics, the complex projective plane, usually denoted P²(C) or CP², is the two-dimensional complex projective space. It is a complex manifold of complex dimension 2, described by three complex coordinates

${\displaystyle (Z_{1},Z_{2},Z_{3})\in \mathbf {C} ^{3},\qquad (Z_{1},Z_{2},Z_{3})\neq (0,0,0)}$

where, however, the triples differing by an overall rescaling are identified:

${\displaystyle (Z_{1},Z_{2},Z_{3})\equiv (\lambda Z_{1},\lambda Z_{2},\lambda Z_{3});\quad \lambda \in \mathbf {C} ,\qquad \lambda \neq 0.}$

That is, these are homogeneous coordinates in the traditional sense of projective geometry.