The two-dimensional space consisting of the set of triples
 |
where triples which are scalar multiples of each other are identified.
Projective Plane PK^2
See also
Projective PlaneExplore with Wolfram|Alpha
Cite this as:
Weisstein, Eric W. "Projective Plane PK^2." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/ProjectivePlanePK2.html