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5 votes
Accepted

Inequality for hermitian matrices

No. For example, let \begin{align*} p_1 = \begin{bmatrix} 1 & 0 \\ 0 & 0 \end{bmatrix}, \ \ p_2 = \begin{bmatrix} 0 & 0 \\ 0 & 1 \end{bmatrix}, \ \ S_1 = \begin{bmatrix} 1 & 1 \\ 1 ...
Nathaniel Johnston's user avatar
3 votes

Inequality for commuting hermitian operators

Yes. Since $S_1$, $S_2$ commute, there exists an orthonormal basis in which they are both diagonal: $S_1={\rm diag}\,(a_1,\ldots,a_n)$ and $S_2={\rm diag}\,(b_1,\ldots,b_n)$, $a_i\geqslant c_1,b_i\...
Fedor Petrov's user avatar

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