in place of \(\FC_u\). Note that \([m^j]\) is understood as \(I_s\otimes[m^j]\), using a common physicist’s convention. In addition a projector \(R=I_m-\sum_j[m^j]\) should be included among the possibilities at the final time \(t_2\), but as it occurs with zero probability it can be ignored. The consistency of the family \(\FC_1\) is easily demonstrated, and the probability \(|c_j|^2\) for the final position \([m^j]\) is an immediate consequence of \eqref{eqn17}.