Reduction of Complex Hamiltonian G-Spaces.
The general Stein union problem is solved: given an increasing sequence of Stein open sets, it is shown that the union is Stein if and only if is Hausdorff separated.
A necessary and sufficient condition, which is a weak converse of a classical theorem of Behnke-Stein, in order that a limit of Stein spaces be again a Stein space is proved.