New answers tagged

2 votes

The matrix norm $\|A\|=\max_{\langle u|u\rangle=1}|\langle u|A|u\rangle|$ in the proof of Lieb's theorem

The short answer is that there are two problems with your argument: The partial derivative of $u^TAu$ you state is wrong More gravely, the whole approach is flawed because you're treating $u$ as a ...
Frederik vom Ende's user avatar

Top 50 recent answers are included