Let $A,B$ be two positive (possibly unbounded) closed operator on a Hilbert space with $AB=BA$. Do we have $A^{1/2}$ commutes with $B^{1/2}$?
I know it is true for bounded operators but I am not sure for unbounded case.
2026-03-28 15:26:59.1774711619
$A^{1/2}$ commutes with $B^{1/2}$
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