Existence of Engel structures
Existence of Engel structures
We develop a construction of Engel structures 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 foliations, there …