Nonseparable UHF algebras I: Dixmier's problem

Ilijas Farah, Takeshi Katsura

Research output: Contribution to journalArticlepeer-review

29 Citations (Scopus)


There are three natural ways to define UHF (uniformly hyperfinite) C*-algebras, and all three definitions are equivalent for separable algebras. In 1967 Dixmier asked whether the three definitions remain equivalent for not necessarily separable algebras. We give a complete answer to this question. More precisely, we show that in small cardinality two definitions remain equivalent, and give counterexamples in other cases. Our results do not use any additional set-theoretic axioms beyond the usual axioms, namely ZFC.

Original languageEnglish
Pages (from-to)1399-1430
Number of pages32
JournalAdvances in Mathematics
Issue number3
Publication statusPublished - 2010 Oct


  • C*-algebras
  • Nonseparable
  • UHF algebras

ASJC Scopus subject areas

  • General Mathematics


Dive into the research topics of 'Nonseparable UHF algebras I: Dixmier's problem'. Together they form a unique fingerprint.

Cite this