Three of the commutation relations of the Lorentz generators are [ J x , J y ] = J z , [ K x , K y ] = − − J z , [ J x , K y ] = K z , where the bracket [ A, B ] = AB − BA is known as the commutator, and the other relations can be found by taking cyclic permutations of x, y, z components (i.e. change x to y, y to z, and z to x, repeat).