Operator trace (source code)

= Operator trace
{title2=$\operatorname{tr}T$}
{wiki=Trace_class}

For a trace-class operator, the series $\operatorname{tr}T=\sum_n\langle Te_n,e_n\rangle$ converges absolutely and is independent of the orthonormal basis. It satisfies $|\operatorname{tr}T|\leq\|T\|_1$.