States separate elements of a C-star algebra
ID: states-separate-elements-of-a-c-star-algebra
Write with both terms Hermitian. At least one is nonzero; its norm equals its spectral radius, so it has a nonzero spectral value. Spectral values attained by C-star states gives a state taking that nonzero value on the chosen term. Both state values on are real, so the corresponding complex value on cannot vanish. This also detects nonzero quasinilpotent elements, which cannot be separated by looking only at their own spectrum.
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