Hostname: page-component-848d4c4894-75dct Total loading time: 0 Render date: 2024-05-01T05:56:59.327Z Has data issue: false hasContentIssue false

Uniform Boundedness for Groups

Published online by Cambridge University Press:  20 November 2018

Irving Glicksberg*
Affiliation:
University of Notre Dame
Rights & Permissions [Opens in a new window]

Extract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

Let G and H be locally compact abelian groups with character groups G*, H*, and let < . , . > denote the pairing between a group and its dual.

In 1952 Kaplansky proved the following result, using the structure of locally compact abelian groups and category arguments.

Theorem 1.1. Let τ: GH be an algebraic homomorphism for which there is a dual τ* : H* → G* (so that < rg, h* > = < g, τ*h* > for all g in G, h* in H*). Then τ is continuous.

The result bears a striking similarity to a well-known fact about Banach spaces which is a consequence of uniform boundedness; the present note is devoted to an analogous “uniform boundedness” for groups, which yields a non-structural proof of Kaplansky's theorem.

Type
Research Article
Copyright
Copyright © Canadian Mathematical Society 1962

References

1. Grothendieck, A., Critères de compacité dans les espaces fonctionelles généraux, Amer. J. Math., 74 (1952), 168186.Google Scholar
2. Loomis, L. H., An introduction to abstract harmonie analysis (New York, 1953).Google Scholar
3. Pettis, B. J., On continuity and openness of homomorphisms in topological groups, Ann. Math. (2), 52 (1950), 293308.Google Scholar
4. Pontrjagin, L., Topological groups (Princeton, 1939).Google Scholar
5. Weil, A., Vintégration dans les groupes topologiques et ses applications (Paris, 1940).Google Scholar