The Local Operator Moment Problem on R

Raúl Curto, PhD

We study the connections between operator moment sequences T={T_1,T_2, ...} of self-adjoint operators on a complex Hilbert space, H, and the local moment sequences (Tx,x)={ (T_1x,x),(T_2x,x) ...} for arbitrary x in H. We provide necessary and sufficient conditions for solving the operator moment problem on the real line, R, and we show that these criteria are automatically valid on compact subsets of R. Applications of the compact case are used to study subnormal operator weighted shifts. A Stampfli-type propagation theorem for subnormal operator weighted shifts is also established. In addition, we discuss the validity of Tchakaloff's Theorem for operator moment sequences with compact support. In the case of a recursively generated sequence of self-adjoint operators, necessary and sufficient conditions for an affirmative answer to the operator recursive moment problem are provided, and the support of the associated representing operator-valued measure is described. The talk is based on joint work with Abderrazzak Ech-charyfy (Mohammed V University in Rabat), Hamza El Azhar (Chouaib Doukkali University) and El Hassan Zerouali (Mohammed V University in Rabat).

To participate in this event virtually via Zoom, go to https://uiowa.zoom.us/j/95316149275.