Hostname: page-component-77c89778f8-gvh9x Total loading time: 0 Render date: 2024-07-17T10:43:51.539Z Has data issue: false hasContentIssue false

Extension problems and non-Abelian duality for C*-algebras

Published online by Cambridge University Press:  17 April 2009

Astrid an Huef
Affiliation:
School of Mathematics and Statistics, The University of New South Wales, New South Wales 2052, Australia, e-mail: astrid@unsw.edu.au
S. Kaliszewski
Affiliation:
School of Mathematical and Physical Sciences, University of Newcastle, NSW 2308, Australia, e-mail: iain.raeburn@newcastle.edu.au
Iain Raeburn
Affiliation:
Department of Mathematics and Statistics, Arizona State University, AZ 85287–1804, United States of America, e-mail: kaliszewski@asu.edu
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.

Suppose that H is a closed subgroup of a locally compact group G. We show that a unitary representation U of H is the restriction of a unitary representation of G if and only if a dual representation Û of a crossed product C*(G) ⋊ (G/H) is regular in an appropriate sense. We then discuss the problem of deciding whether a given representation is regular; we believe that this problem will prove to be an interesting test question in non-Abelian duality for crossed products of C*-algebras.

Type
Research Article
Copyright
Copyright © Australian Mathematical Society 2007

References

[1]Deicke, K., Pask, D. and Raeburn, I., ‘Coverings of directed graphs and crossed products of C*-algebras by coactions of homogeneous spaces’, Internat. J. Math. 14 (2003), 773789.CrossRefGoogle Scholar
[2]Echterhoff, S., ‘Duality of induction and restriction for abelian twisted covariant systems’, Math. Proc. Camb. Phil. Soc. 116 (1994), 301315.CrossRefGoogle Scholar
[3]Echterhoff, S., Kaliszewski, S. and Quigg, J., ‘Maximal coactions’, Internat. J. Math. 15 (2004), 4761.CrossRefGoogle Scholar
[4]Echterhoff, S., Kaliszewski, S., Quigg, J. and Raeburn, I., ‘A categorical approach to imprimitivity theorems for C*-dynamical systems’, Memoirs Amer. Math. Soc. 180 (2006), 1169.CrossRefGoogle Scholar
[5]Echterhoff, S., Kaliszewski, S. and Raeburn, I., ‘Crossed products by dual coactions of groups and homogeneous spaces’, J. Operator Theory 39 (1998), 151176.Google Scholar
[6]Echterhoff, S. and Quigg, J., ‘Full duality for coactions of discrete groups’, Math. Scand. 90 (2002), 267288.CrossRefGoogle Scholar
[7]Green, P., ‘The local structure of twisted covariance algebras’, Acta Math. 140 (1978), 191250.CrossRefGoogle Scholar
[8]an Huef, A., Kaliszewski, S. and Raeburn, I., ‘Covariant representations of Hecke algebras and imprimitivity for crossed products by homogeneous spaces’, (preprint) arXiv:math.0A/0509291.Google Scholar
[9]an Huef, A. and Raeburn, I., ‘Twisted actions and the obstruction to extending unitary representations of subgroups’, J. Pure Appl. Algebra 194 (2004), 299309.CrossRefGoogle Scholar
[10]Kaliszewski, S. and Quigg, J., ‘Mansfield imprimitivity for full crossed products’, Trans. Amer. Math. Soc. 357 (2005), 20212042.CrossRefGoogle Scholar
[11]Kaliszewski, S., Quigg, J. and Raeburn, I., ‘Duality of restriction and induction for C*-coactions’, Trans. Amer. Math. Soc. 349 (1997), 20852113.CrossRefGoogle Scholar
[12]Mansfield, K., ‘Induced representations of crossed products by coactions’, J. Funct. Anal. 97 (1991), 112161.CrossRefGoogle Scholar
[13]Pask, D., Quigg, J. and Raeburn, I., ‘Coverings of k-graphs’, J. Algebra 289 (2005), 161191.CrossRefGoogle Scholar
[14]Raeburn, I. and Williams, D.P., Morita Equivalence and Continuous-Trace C*-Algebras, Math. Surveys and Monographs 60 (Amer. Math. Soc, Providence, R.I., 1998).CrossRefGoogle Scholar