  Various Seiberg-Witten Floer cohomologies are defined for a closed, oriented
3-manifold; and if it is the mapping torus of an area-preserving surface
automorphism, it has an associated periodic Floer homology as defined by
Michael Hutchings. We construct an isomorphism between a certain version of
Seiberg-Witten Floer cohomology and the corresponding periodic Floer homology,
and describe some immediate consequences.
