Order preservation by the positive square root
ID: order-preservation-by-the-positive-square-root
For Positive elements of a C-star algebra , inversion reverses the order of strictly positive elements, so for . Subtracting their square-root resolvent integral in a C-star algebra formulas givesThe integrand is positive, and the positive cone is closed, so the norm limit of these integrals is positive. No commutativity of and is required. In particular, for positive implies , even though squaring itself is not generally order preserving.
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