Matrices with normal defect one

D. S. Kaliuzhnyi-Verbovetskyi, I. M. Spitkovsky, H. J. Woerdeman

A $n\times n$ matrix $A$ has normal defect one if it is not normal, however can be embedded as a north-western block into a normal matrix of size $(n+1)\times (n+1)$. The latter is…