Complex symmetry of first-order differential operators on Hardy space

Abstract

Given holomorphic functions ${\psi }_0$ and ${\psi }_1$, we consider first-order differential operators acting on Hardy space, generated by the formal differential expression $E({\psi }_0,{\psi }_1)f(z)={\psi }_0(z)f(z)+{\psi }_1(z)f^{\prime }(z)$. We characterize these operators which are complex symmetric with respect to weighted composition conjugations. In parallel, as a basis of comparison, a characterization for differential operators which are hermitian is carried out. Especially, it is shown that hermitian differential operators are contained properly in the class of $\calC$-selfadjoint differential operators. The calculation of the point spectrum of some of these operators is performed in detail.

14 pages