2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/146755We give sufficient conditions for the naturallity of the exterior differential under Sobolev mappings. In other words we study the validity of the equation $d f^* α= f^* dα$ for a smooth form $α$ and a Sobolev map $f$.9 pagesAnalysis of PDEs46E35, 58Dxxtext