  On the basis of Sz. Nagy-Foia\c{s}-Langer and von Neumann-Wold
decompositions, two decompositions for dissipative linear relations are given
and they are realized by transforming invariant subspaces for contractions, by
means of the Z transform. These decompositions permit the separation of the
selfadjoint and completely nonselfadjoint parts of a dissipative relation.
