Czechoslovak Mathematical Journal

, Volume 62, Issue 4, pp 901–917 | Cite as

Essential normality for certain finite linear combinations of linear-fractional composition operators on the Hardy space H 2



In 1999 Nina Zorboska and in 2003 P. S.Bourdon, D. Levi, S.K.Narayan and J.H. Shapiro investigated the essentially normal composition operator \({C_\varphi }\), when φ is a linear-fractional self-map of D. In this paper first, we investigate the essential normality problem for the operator T w \({C_\varphi }\) on the Hardy space H 2, where w is a bounded measurable function on ∂D which is continuous at each point of F(φ), φS(2), and T w is the Toeplitz operator with symbol w. Then we use these results and characterize the essentially normal finite linear combinations of certain linear-fractional composition operators on H 2.


Hardy spaces essentially normal composition operator linear-fractional transformation 

MSC 2010



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Copyright information

© Institute of Mathematics of the Academy of Sciences of the Czech Republic, Praha, Czech Republic 2012

Authors and Affiliations

  1. 1.Department of Mathematics, College of SciencesShiraz UniversityShirazIran

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