Maximal coactions

Siegfried Echterhoff, Steven Kaliszewski, John Quigg

Research output: Contribution to journalArticlepeer-review

32 Scopus citations


A coaction δ of a locally compact group G on a C*-algebra A is maximal if a certain natural map from A x δ G x δ G onto A⊗K(L2(G)) is an isomorphism. All dual coactions on full crossed products by group actions are maximal; a discrete coaction is maximal if and only if A is the full cross-sectional algebra of the corresponding Fell bundle. For every nondegenerate coaction of G on A, there is a maximal coaction of G on an extension of A such that the quotient map induces an isomorphism of the crossed products.

Original languageEnglish (US)
Pages (from-to)47-61
Number of pages15
JournalInternational Journal of Mathematics
Issue number1
StatePublished - Feb 2004


  • C*-algebra
  • Coaction
  • Crossed product
  • Duality
  • Locally compact group

ASJC Scopus subject areas

  • Mathematics(all)


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