Acknowledgement
Supported by : Changwon National University
References
- M. Cho, R. E. Curto and W. Y. Lee, Triangular Toeplitz contractions and Cowen sets for analytic polynomials, Proc. Amer. Math. Soc. 130 (2002), 3957-3604.
- C. C. Cowen, Hyponormality of Toeplitz operators, Proc. Amer. Math. Soc. 103 (1988), 809-812. https://doi.org/10.1090/S0002-9939-1988-0947663-4
- R. E. Curto and W. Y. Lee, Joint hyponormality of Toeplitz pairs, Memoirs Amer. Math. Soc. no. 712, Amer. Math. Soc., Providence, 2001.
- I. Gohberg, S. Goldberg and M.A. Kaashoek, Classes of Linear Operators, Vol II, Birkhauser Verlag, Basel, 1993.
- I. S. Hwang and W. Y. Lee, Hyponormality of Toeplitz operators with polynomial and symmetric-type symbols, Integral Equations and Operator Theory 50(3) (2004), 363-373. https://doi.org/10.1007/s00020-002-1235-3
- T. Nakazi and K. Takahashi, Hyponormal Toeplitz operators and extremal problems of Hardy spaces, Trans. Amer. Math. Soc. 338 (1993), 753-769. https://doi.org/10.1090/S0002-9947-1993-1162103-7
- I. Schur, Uber Potenzreihen, die im Innern des Einheitskreises Beschrankt sind [I], Journal fur die reine und angewandte Mathematik 147 (1917), 205-232.