where we have assumed that the disordered Hall probe l2 transmits only Nl2 < Nwide edge channels because of the barrier in the lead. For the field direction shown in Fig. 87 one has, under the assumption of no inter-edge channel scattering from constriction to probe l2, Ts→l1 =Nwide, Ts→l2 = Tl2→l1 = 0, and Tl1→l2 = max(0,Nl2 − Nmin). Equation (4.15) then leads to a Hall resistance RH ≡ (μl1 − μl2 )/eI given by