Abstract:
It is shown that every irreducible unitary representation of a locally compact separable group with nontrivial first cohomology is unseparable from the identity representation in the space of irreducible unitary representations. For compactly generated groups the statement can be sharpened: a nontrivial cocycle in such a representation is in a certain sense the limit of trivial cocycles in irreducible representations. A survey is given of the connections between the notions indicated in the title.
Bibliography: 17 titles.