A distance formula for tuples of operators

Priyanka Grover, Sushil Singla

For a tuple of operators $\mathbf{A}=(A_1,\dots ,A_d)$, $\text{dist}(\mathbf{A},{\mathbb{C}}^d\mathbf{I})$ is defined as $\min\limits_{\boldsymbol{z} \in \mathbb C^d}…