• Fotios C Paliogiannis

Articles written in Proceedings – Mathematical Sciences

• On Commuting Operator Exponentials, II

We prove that, under sufficient conditions on the spectra,

$$e^M e^N\subseteq e^N e^M\Rightarrow MN\subseteq NM,$$

where 𝑁 is an unbounded normal operator and 𝑀 is a bounded normal operator in the Hilbert space.

• A Note on the Fuglede-Putnam Theorem

We prove the following generalization of the Fuglede–Puntam theorem. Let 𝑁 be an unbounded normal operator in the Hilbert space, and let 𝐴 be an unbounded self-adjoint operator such that $D(N)\subseteq D(A)$. Then, $AN\subseteq N^∗A\Rightarrow AN^∗\subseteq NA$.

• Proceedings – Mathematical Sciences

Volume 131, 2021
All articles
Continuous Article Publishing mode

• Editorial Note on Continuous Article Publication

Posted on July 25, 2019