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Algebras of Bounded Analytic Functions containing the Disk Algebra

Published online by Cambridge University Press:  20 November 2018

Keiji Izuchi
Affiliation:
Kanagawa University, Yokohama, Japan
Yuko Izuchi
Affiliation:
Kanagawa Dental College, Yokosuka, Japan
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Let D be the open unit disk and let ∂D be its boundary. We denote by C the algebra of continuous functions on ∂d, and by L the algebra of essentially bounded measurable functions with respect to the normalized Lebesgue measure m on ∂D. Let H be the algebra of bounded analytic functions on D. Identifying with their boundary functions, we regard H as a closed subalgebra of L. Let A = H Pi C, which is called the disk algebra. The algebras A and H have been studied extensively [5, 6, 7]. In these fifteen years, norm closed subalgebras between H and L, called Douglas algebras, have received considerable attention in connection with Toeplitz operators [12]. A norm closed subalgebra between A and H is called an analytic subalgebra. In [2], Dawson studied analytic subalgebras and he remarked that there are many different types of analytic subalgebras. One problem is to study which analytic subalgebras are backward shift invariant. Here, a subset E of H is called backward shift invariant if

Type
Research Article
Copyright
Copyright © Canadian Mathematical Society 1986

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