2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/64297A classical result asserts that the complex projective plane modulo complex conjugation is the 4-dimensional sphere. We generalize this result in two directions by considering the projective planes over the normed real division algebras and by considering the complexifications of these four projective planes.28 pages, 1 figure, LatexDifferential GeometryAlgebraic Geometry53C30text