Real point
In geometry, a real point is a point in the complex projective plane with homogeneous coordinates (x,y,z) for which there exists a nonzero complex number λ such that λx, λy, and λz are all real numbers. This definition can be widened to a complex projective space of arbitrary finite dimension as follows: ( u 1 , u 2 , … , u n ) {\displaystyle (u_{1},u_{2},\ldots ,u_{n})} are the homogeneous coordinates of a real point if there exists a nonzero complex number λ such that the coordinates of ( λ u 1 , λ u 2 , … , λ u n ) {\displaystyle (\lambda u_{1},\lambda u_{2},\ldots ,\lambda u_{n})} are all real.