🌐EnglishEnglishDeutschEspañolFrançaisNederlandsPortuguêsSvenskaРусскийไทย한국어中文日本語EntityQ2063099· pop 13· linked from 118 articlesPoincaré dualityduality that relates homology and cohomology groups for oriented closed manifoldsConnectionshomologyEntityfunctorEntityCategoriesDuality (mathematics)Homology theoryManifoldsTheorems in algebraic topology