ON THE NUMERICAL RANGE OF EP MATRICES

Dimitrios Pappas

DOI Number
https://doi.org/10.22190/FUMI2004079P
First page
1079
Last page
1089

Abstract


In this work we study the numerical range $W(T)$ of EP matrices or operators having a canonical form $T =  U(A\oplus 0)U^* $ in the case when $0 \notin W(A)$. As a result, we define the distance $d(W(A,T))$ between the sets $W(A)$ and $W(T)$ and investigate their connenctions, giving also upper and lower bounds for the distance $d(W(A^{-1},T^\dagger))$.   Finally we present the form of their angular numerical range $F(T)$ and its connection with $F(T^\dagger)$.

Keywords

Numerical Range, Angular numerical range, EP matrices, Moore-Penrose inverse.

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References


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DOI: https://doi.org/10.22190/FUMI2004079P

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