Abstract: The spectral mapping theorem is one of the most important results in operator theory. However, the same statement fails for the numerical range. In this talk, we provide several examples to reveal the relation between spectrum and numerical range. Then we discuss a weak version of the spectral mapping theorem that can be extended for the numerical range. This point of view leads us to Halmos conjecture and theorems of Berger-Stampfli and Drury.

Speaker's homepage: https://www.mat.ulaval.ca/departement-et-professeurs/direction-personnel-et-etudiants/professeurs/fiche-de-professeur/show/mashreghi-javad/