M. Aouichaoui

collaborators

4 papers

math.FA2026

A proof of the Fong--Tsui conjecture

Mohamed Amine Aouichaoui, Fuad Kittaneh, Yicen Ma

We prove that a bounded operator $T$ on a complex Hilbert space is self-adjoint whenever $|T|\leq|\re T|$, as conjectured by Fong and Tsui \cite{FT}.

math.FA2026

Sharp spectral constants for scaled $q$ -numerical ranges

Mohamed Amine Aouichaoui, Ryan O'Loughlin

For $n \geq 2$ , $A \in M_{n} (C)$ and $0 < ∣ q ∣ \leq 1$ , let $Ω_{q} (A) = q^{- 1} W_{q} (A)$ be the scaled $q$ -numerical range. We prove that for every $γ \geq 1$ , \[ Ω_{η(γ)}(A) =\bigcup_{κ…

math.FA2026

On $m$ -partial isometries: spectra, weighted shifts, and similarity

Mohamed Amine Aouichaoui, Michał Buchała, Stephan Ramon Garcia

The aim of this paper is to study $m$ -partial isometries on Hilbert spaces, a natural extension of partial isometries and $m$ -isometries. We establish structural and spectral resul…

math.GM2023

The square root theorem for positive semidefinite matrices and their monotonicity

Mohamed Amine Aouichaoui, Mohammed Hichem Mortad

In this note, simple proofs of certain well-known results involving the positive square root of positive matrices are given.

A proof of the Fong--Tsui conjecture

Sharp spectral constants for scaled q-numerical ranges

On m-partial isometries: spectra, weighted shifts, and similarity

The square root theorem for positive semidefinite matrices and their monotonicity

Sharp spectral constants for scaled $q$ -numerical ranges

On $m$ -partial isometries: spectra, weighted shifts, and similarity