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Found this statement in Quantum Mechanics by David McIntyre and was wondering how this is proven.


marked as duplicate by user191954, Cosmas Zachos, Aaron Stevens, Jon Custer, ZeroTheHero Oct 14 '18 at 5:01

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    $\begingroup$ Can you give a direct quote and some more context? $\endgroup$ – Aaron Stevens Oct 13 '18 at 4:35