Corrections and additions to ‘Inverse continuity on the boundary of the numerical range’

Abstract

This note corrects a theorem characterizing the points where weak continuity can fail for the inverse numerical range map.

Keywords:

• field of values
• numerical range
• inverse continuity
• weak continuity

AMS Subject Classifications:

• Primary: 15A60
• 47A12; Secondary: 54C08

Acknowledgements

We are very grateful to Stephan Weis for pointing out the deficiency in the original statement of Theorem 2.1 and for continued discussions during the preparation of this note.

Notes

No potential conflict of interest was reported by the authors.