In Srednicki's text on quantum field theory, he has a chapter on quantum Lorentz invariance. He presents the commutation relations between the generators of the Lorentz group (equation 2.16) as follows:(adsbygoogle = window.adsbygoogle || []).push({});

$$[M^{\mu\nu},M^{\rho\sigma}] = i\hbar\Big(g^{\mu\rho}M^{\nu\sigma}-(\mu\leftrightarrow\nu)\Big)-(\rho\leftrightarrow\sigma)$$

I have never seen the strange double-arrow notation in any linear algebra book before. Is this notation at all standard and if so, what does it mean?

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# Lie Algebra of the Lorentz group - a weird notation?

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