Partially defined σ-derivations on semisimple Banach algebras

Tsiu Kwen Lee, Cheng Kai Liu

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


Let A be a semisimple Danach algebra with a linear automorphism σ and let δ: I → A be a σ-derivation, where I is an ideal of A. Then Φ(δ)(I ∩ σ(I)) = 0, where Φ(δ) is the separating space of δ. As a consequence, if I is an essential ideal then the σ-derivation δ is closable. In a prime C*-algebra, we show that every σ-derivation defined on a nonzero ideal is continuous. Finally, any linear map on a prime semisimple Danach algebra with nontrivial idempotents is continuous if it satisfies the σ-derivation expansion formula on zero products.

Original languageEnglish
Pages (from-to)193-202
Number of pages10
JournalStudia Mathematica
Issue number2
Publication statusPublished - 2009 Mar 18

All Science Journal Classification (ASJC) codes

  • Mathematics(all)

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