Spin obeys commutation relations analogous to those of the orbital angular momentum : [ S ^ ^ j , S ^ ^ k ] = i ℏ ℏ ε ε j k l S ^ ^ l , where ε jkl is the Levi-Civita symbol. It follows (as with angular momentum) that the eigenvectors of S ^ ^ 2 and S ^ ^ z (expressed as kets in the total S basis) are S ^ ^ 2 | s , m s ⟩ ⟩ = ℏ ℏ 2 s ( s + 1 ) | s , m s ⟩ ⟩ , S ^ ^ z | s , m s ⟩ ⟩ = ℏ ℏ m s | s , m s ⟩ ⟩ .