# ON m-ISOMETRIC TOEPLITZ OPERATORS

• Ko, Eungil (Department of Mathematics Ewha Womans University) ;
• Lee, Jongrak (Institute of Mathematical Sciences Ewha Womans University)
• Accepted : 2017.10.17
• Published : 2018.03.31

#### Abstract

In this paper, we study m-isometric Toeplitz operators $T_{\varphi}$ with rational symbols. We characterize m-isometric Toeplitz operators $T_{\varphi}$ by properties of the rational symbols ${\varphi}$. In addition, we give a necessary and sufficient condition for Toeplitz operators $T_{\varphi}$ with analytic symbols ${\varphi}$ to be m-expansive or m-contractive. Finally, we give some results for m-expansive and m-contractive Toeplitz operators $T_{\varphi}$ with trigonometric polynomial symbols ${\varphi}$.

#### Acknowledgement

Supported by : National Research Foundation of Korea(NRF)

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