Hostname: page-component-cd9895bd7-7cvxr Total loading time: 0 Render date: 2024-12-26T08:49:22.941Z Has data issue: false hasContentIssue false

Angular Derivatives and Compact Composition Operators on the Hardy and Bergman Spaces

Published online by Cambridge University Press:  20 November 2018

Barbara D. MacCluer
Affiliation:
University of Virginia, Charlottesville, Virginia
Joel H. Shapiro
Affiliation:
Michigan State University, East Lansing, Michigan
Rights & Permissions [Opens in a new window]

Extract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

Let U denote the open unit disc of the complex plane, and φ a holomorphic function taking U into itself. In this paper we study the linear composition operator Cφ defined by Cφf = f º φ for f holomorphic on U. Our goal is to determine, in terms of geometric properties of φ, when Cφ is a compact operator on the Hardy and Bergman spaces of φ. For Bergman spaces we solve the problem completely in terms of the angular derivative of φ, and for a slightly restricted class of φ (which includes the univalent ones) we obtain the same solution for the Hardy spaces Hp (0 < p < ∞). We are able to use these results to provide interesting new examples and to give unified explanations of some previously discovered phenomena.

Type
Research Article
Copyright
Copyright © Canadian Mathematical Society 1986

References

1. Ahern, P. R., The mean modulus and derivative of an inner function, Indiana Univ. Math. J. 25 (1979), 311347.Google Scholar
2. Ahern, P. R., On the behavior near a torus of functions holomorphic in the hall, Pacific J. Math. 707 (1983), 267278.Google Scholar
3. Ahern, P. R. and Clark, D. N., On inner functions with Hp derivative, Michigan Math. J. 21 (1974), 115127.Google Scholar
4. Ahlfors, L. V., Conformai invariants (McGraw-Hill, New York, 1973).Google Scholar
5. Boyd, D. M., Composition operators on the Bergman space, Colloq. Math. 34 (1975), 127136.Google Scholar
6. Burckel, R. B., Iterating analytic self-maps of the disc, American Math. Monthly 88 (1981), 396407.Google Scholar
7. Carleson, L., Interpolation by hounded analytic functions and the Corona problem, Annals of Math. 76 (1962), 547559.Google Scholar
8. Caughran, J. G. and Schwartz, H. J., Spectra of compact composition operators, Proc. Amer. Math. Soc. 51 (1970), 127130.Google Scholar
9. Cima, J. A., Stanton, C. S. and Wogen, W. R., On boundedness of composition operators on H2;(B2), Proc. Amer. Math. Soc. 91 (1984), 217222.Google Scholar
10. Cima, J. A. and Wogen, W. R., A Carleson measure theorem for the Bergman space on the ball, J. Operator Theory 7 (1982), 157165.Google Scholar
11. Cima, J. A. and Wogen, W. R., Unbounded composition operators on H2(B2), Preprint, University of North Carolina at Chapel Hill.Google Scholar
12. Cowen, C. C., Composition operators on H2 , J. Operator Theory 9 (1983), 77106.Google Scholar
13. Duren, P. L., Theory of Hp spaces (Academic Press, New York, 1970).Google Scholar
14. Halmos, P. R., Measure theory (Van Nostrand, Princeton, N.J., 1950).CrossRefGoogle Scholar
15. Hastings, W. W., A Carleson measure theorem for Bergman spaces, Proc. Amer. Math. Soc. 52 (1975), 237241.Google Scholar
16. Kamowitz, H., The spectra of composition operators on Hp , J. Functional Analysis 18 (1975), 132150.Google Scholar
17. Luecking, D., A technique for characterizing Carleson measures on Bergman spaces, Proc. Amer. Math. Soc. 87 (1983), 656660.Google Scholar
18. MacCluer, B. D., Spectra of automorphism-induced composition operators on HP(BN), J. London Math. Soc. (2) 30 (1984), 95104.Google Scholar
19. MacCluer, B. D., Spectra of compact composition operators on HP(BN), Analysis 4 (1984), 87103.Google Scholar
20. MacCluer, B. D., Compact composition operators on Hp(BN), Michigan Math. J. 32 (1985), 237248.Google Scholar
21. McDonald, G. and Sundberg, C., Toeplitz operators on the disc, Indiana Univ. Math. J. 28 (1979), 595611.Google Scholar
22. Nagel, A., Rudin, W. and Shapiro, J. H., Tangential boundary behavior of functions in Dirichlet-type spaces, Annals of Math. 116 (1982), 331360.Google Scholar
23. Nevanlinna, R., Analytic functions (Springer-Verlag, New York, 1970).CrossRefGoogle Scholar
24. Nordgren, E., Composition operators, Can. J. Math. 20 (1968), 442449.Google Scholar
25. Riesz, M., Sur certaines inequalités dans la théorie des fonctions avec quelques remarques sur les geometries non-euclidiennes, Kungl. Fysiogr. Sällsk i Lund 1 (1931), 1838.Google Scholar
26. Rudin, W., Real and complex analysis, 2nd ed. (McGraw-Hill, New York, 1974).Google Scholar
27. Rudin, W., Function theory in the unit ball of CN (Springer-Verlag, New York, 1980).CrossRefGoogle Scholar
28. Ryff, J. V., Subordinate Hp functions, Duke Math. J. 33 (1966), 347354.Google Scholar
29. Schwartz, H. J., Composition operators on Hp , Thesis, University of Toledo, Toledo, Ohio, 1969.Google Scholar
30. Shapiro, J. H. and Taylor, P. D., Compact, nuclear and Hilbert-Schmidt composition operators on H2 , Indiana Univ. Math. J. 23 (1973), 471496.Google Scholar
31. Stegenga, D. A., Multipliers of the Dirichlet space, Illinois J. Math. 24 (1980), 113139.Google Scholar
32. Tsuji, M., Potential theory in modern function theory (Maruzen, Tokyo, 1959).Google Scholar
33. Voas, C., Toeplitz operators and univalent functions, Thesis, University of Virginia, 1980.Google Scholar