Conservation of angular momentum is generated by spatatial rotation invariance. Space rotation invariance is indeed part of the Lorentz group. But I suspect the original poster was interested in the symmetries related to the Lorentz boost, not by the spatial rotation part of the Lorentz group.dextercioby said:Angular momentum. Immediate by Noether's theorem for classical fields.
I was thinking the same thing but there are many 4-vector invariants in SR. Energy-momentum, space-time. The classical conservation laws have one specific quantity conservered not a variety.selfAdjoint said:The Lorentz transformations by definition preserve the four-interval [tex]c^2t^2 - x^2 - y^2 - z^2[/tex].