Three-manifolds admitting Morse–Smale diffeomorphisms without heteroclinic curves

We give the topological classification of three-dimensional closed orientable manifolds admitting Morse–Smale diffeomorphisms without heteroclinic curves: these manifolds are either the three-dimensional sphere or connected sums of S2×S1ʹs and we give a formula relating the number of sinks, sources and saddle periodic points to the topology of the manifold.