Hmm, the greek letters are definitely time + spatial, but in the second included equation we divide the 6 generators into three spatial ones (rotations) and three temporal ones (boosts), so the roman ones are used when seperating them like that.
And it's mostly minus metric.
This is the defining generator of the Lorentz group
which is then divided into subgroups for rotations and boosts
And I then want to find the commutation relation [J_m, J_n] (and [J_m, K_n] ). I'm following this derivation, but am having a hard time to understand all the steps:
especially...