Home›Geometric topology›real projective plane🌐EnglishEnglishEspañolFrançaisItalianoNederlandsPolskiPortuguêsРусский中文日本語EntityQ633815· pop 15· linked from 123 articlesreal projective planea compact non-orientable two-dimensional manifoldAvailable in 15 languagesEspañolFrançais中文日本語РусскийPortuguêsCzechEsperantoFinnishGreekConnectionshomeomorphismEntitysurfaceEntityCategoriesGeometric topologySurfaces