On Discrete Spectra of Bergman–Toeplitz Operators with Harmonic Symbols

Self-commutators of composition operators with monomial symbols on the Bergman space

Let $varphi(z)=z^m, z in mathbb{U}$, for some positive integer $m$, and $C_varphi$ be the composition operator on the Bergman space $mathcal{A}^2$ induced by $varphi$. In this article, we completely determine the point spectrum, spectrum, essential spectrum, and essential norm of the operators $C^*_varphi C_varphi, C_varphi C^*_varphi$ as well as self-commutator and anti-self-commutators of $C_...

Pseudodifferential operators with homogeneous symbols

We prove boundedness of pseudodifferential operators with symbols satisfying the conditions |∂ ξ ∂ xa(x, ξ)| ≤ Cβ,γ |ξ|m−|β|+|γ| on homogeneous Besov-Lipschitz and Triebel-Lizorkin spaces

Pseudodifferential Operators with Rough Symbols

In this work, we develop L boundedness theory for pseudodifferential operators with rough (not even continuous in general) symbols in the x variable. Moreover, the B(L) operator norms are estimated explicitly in terms of scale invariant quantities involving the symbols. All the estimates are shown to be sharp with respect to the required smoothness in the ξ variable. As a corollary, we obtain L...

Toeplitz operators with special symbols

Hyponormality of Toeplitz Operators with Rational Symbols

In this article we introduce a notion of ‘division’ for rational functions and then give a criterion for hyponormality of Tg+f (f, g are rational functions) in the cases where g divides f . Furthermore we show that we may assume, without loss of generality, that g divides f when we consider the hyponormality of Tg+f .