“…but only valid for h ∈ {0, 1}. Proceeding by analogy with the m = 0 case, we now Ansatz 20) where the dependence of the additional Θ factor on the coordinates (t, r, φ) is fixed to be Φ h (r)Ψ m (φ) in order to ensure that the potential A EM h,m (U h,m , V h,m , T h,m ) is still an SL(2, R) highest-weight U(1)-eigenstate. Again, note that this is a nonlinear superposition in θ because the functions U h,m (θ), V h,m (θ) need not be identical to the functions P h,m (θ), S h,m (θ) introduced in sections 3 and 4.…”