# QED parity invariance and gamma 5 [closed]

Why does the invariance of parity of QED indicate that gamma-5 can not appear in Feynman diagrams?

## closed as unclear what you're asking by sammy gerbil, ZeroTheHero, AccidentalFourierTransform, Daniel Griscom, JamalSApr 12 '18 at 12:24

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• The claim is false. As $\gamma_5^2=1$, you can always insert factors of $\gamma_5$ here and there. – AccidentalFourierTransform Mar 27 '18 at 15:52