期刊名称:International Journal of Mathematics and Mathematical Sciences
印刷版ISSN:0161-1712
电子版ISSN:1687-0425
出版年度:2007
卷号:2007
DOI:10.1155/2007/39819
出版社:Hindawi Publishing Corporation
摘要:Let 𝔻={z∈ℂ:|z|<1} be the open unit
disk in the complex plane ℂ. Let A2(𝔻) be the space of analytic functions on 𝔻 square integrable
with respect to the measure dA(z)=(1/π)dx dy. Given a∈𝔻 and f any
measurable function on 𝔻, we define the function
Caf by Caf(z)=f(ϕa(z)), where ϕa∈Aut(𝔻). The map Ca is a composition operator on L2(𝔻,dA) and A2(𝔻) for all a∈𝔻. Let ℒ(A2(𝔻)) be the space of
all bounded linear operators from A2(𝔻) into itself. In this article, we have shown that CaSCa=S for all a∈𝔻 if and only if
∫𝔻S˜(ϕa(z))dA(a)=S˜(z), where S∈ℒ(A2(𝔻)) and S˜ is the Berezin symbol of S.