2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/215140We develop a construction of Engel stuctures on 4-manifolds based on decompositions of manifolds into round handles. This allows us to show that all parallelizable 4-manifolds admit an Engel structure. We also show that, given two Engel manifolds M_1,M_2 satisfying a certain condition on the characteristic foliation, there is an Engel structure on M_1#M_2#(S^2xS^2) which is closely related to the original Engel structures.57 pages, 14 figuresGeometric TopologySymplectic Geometry57R (primary); 58A, 53D (secondary)text