In order to desc¡ibe a physical system which is Lorentz invaria¡t one must construct from the fundamental dynamical va¡iables for the system ten Hermitian operators: H, Pj, Ji, K^j}\) ...In order to desc¡ibe a physical system which is Lorentz invaria¡t one must construct from the fundamental dynamical va¡iables for the system ten Hermitian operators: H, Pj, Ji, K^j}\) where (where j=1,2,3) satisfying [Jj,Pk]=iℏϵijkPl where ℏ=h/2π, h is Planck's constant, c is the speed of light, δij is the Kronecker delta symbol and ϵijl is the Levi-Civita permutation symbol.
