  Seiberg-Witten (Floer) theory, Ozsvath-Szabo's Heegaard Floer theory,
Hutchings's embedded contact homology, in different stages of development,
define (or are expected to define) packages of invariants for 3- and
4-manifolds (including manifolds with boundary and manifolds with certain types
of corners). We describe what are known about their relationship, what are
expected, and raise some questions along the way.
