Hyponormality of Trigonometric Toeplitz Operators
نویسندگان
چکیده
In this paper we establish a tractable and explicit criterion for the hyponormality of arbitrary trigonometric Toeplitz operators, i.e., Toeplitz operators Tφ with trigonometric polynomial symbols φ. Our criterion involves the zeros of an analytic polynomial f induced by the Fourier coefficients of φ. Moreover the rank of the selfcommutator of Tφ is computed from the number of zeros of f in the open unit disk D and in C \ D counting multiplicity.
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