COMPLEX ANALYSIS AND OPERATOR THEORY, cilt.12, sa.1, ss.55-79, 2018 (SCI-Expanded)
In this work we study the essential spectra of composition operators on weighted Bergman spaces of analytic functions which might be termed as "quasi-parabolic." This is the class of composition operators on with symbols whose conjugate with the Cayley transform on the upper half-plane are of the form , where and . We especially examine the case where is discontinuous at infinity. A similar method used in Gul (J Math Anal Appl 377:771-791, 2011) for Hardy spaces is used to show that this type of composition operators fall in a C*-algebra of Toeplitz operators and Fourier multipliers. This method enables us to provide new examples of essentially normal composition operators and to calculate their essential spectra.