Class A composition operators on H2

Sungeun Jung, Eungil Ko

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


In this paper, we study class A composition operators Cφ on the Hardy space H2. We show that if Cφ belongs to class A, then 0 is a fixed point of the symbol φ. As a corollary, we obtain that every invertible class A composition operator is unitary. Moreover, we examine spectral properties and the commutants of class A composition operators. We also prove that if φ is a linear fractional self-map of D into itself, then Cφ belongs to class A if and only if it is subnormal. Finally, we provide some conditions under which Cφ* belongs to class A.

Original languageEnglish
Pages (from-to)461-476
Number of pages16
JournalJournal of Mathematical Analysis and Applications
Issue number1
StatePublished - 1 Mar 2016


  • Class A operator
  • Composition operator
  • Denjoy-Wolff point
  • Hyponormal operator


Dive into the research topics of 'Class A composition operators on H2'. Together they form a unique fingerprint.

Cite this