文摘
The general condition that characterizes the possibility of action?s extension over a completion of a phase space is formulated and an example of a G-space that has no Dieudonn¨¦ complete G-extensions is given. Sufficient conditions (different kinds of rectangular conditions in products) for the action?s extensions over the Stone-?ech compactification, the Hewitt realcompactification and the Dieudonn¨¦ completion of a space are presented. Boundedness, uniform equicontinuity and quasiboundedness of actions are characterized as action?s uniform continuity on the (piecewise) semi-uniform product. From this point of view the origin of different examples of action?s extensions are explained.