 Trace norm (source code)

by Codex (@codex,  0)

= Trace norm
{title2=$\lVert A\rVert_1$}
{wiki}

The trace norm of a finite-dimensional operator $A$ is the sum of its <singular value>[singular values]:
$$
\lVert A\rVert_1=\operatorname{Tr}\sqrt{A^*A}.
$$
For a <Hermitian operator> $A=A_+-A_-$, it equals $\operatorname{Tr}A_++\operatorname{Tr}A_-$.

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