Ryan O’Loughlin

collaborators

2 papers

math.FA2025

Bounded Toeplitz Products on the Hardy Space

Ryan O'Loughlin

A Toeplitz operator on the Hardy space of the unit circle is bounded if and only if its symbol is bounded. For two Toeplitz operators, there are no known function-theoretic conditi…

math.FA2024

On the Crouzeix ratio for $N \times N$ matrices

Bartosz Malman, Javad Mashreghi, Ryan O'Loughlin +1

The Crouzeix ratio $ψ (A)$ of an $N \times N$ complex matrix $A$ is the supremum of $∥ p (A) ∥$ taken over all polynomials $p$ such that $∣ p ∣ \leq 1$ on the numerical range of $A$ . It i…

Bounded Toeplitz Products on the Hardy Space

On the Crouzeix ratio for N×N matrices

On the Crouzeix ratio for $N \times N$ matrices