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Bibliographic Details
Main Authors: O'Loughlin, Ryan, Rani, Jyoti
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2603.15536
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Table of Contents:
  • We study spectral constants for convex domains $Ω$ containing the spectrum of an operator. We extend the Crouzeix--Palencia framework by obtaining bounds depending on a parameter $γ$ and relating these bounds to geometric properties of $Ω$ and the numerical range $W(A)$. We generalise the proof that the numerical range is a $1+\sqrt{2}$-spectral set to scaled $q$-numerical ranges. We also propose a generalisation of Crouzeix's Conjecture in the context of $q$-numerical ranges.