857493.fig.008a
(a)
857493.fig.008b
(b)
857493.fig.008c
(c)
Figure 8: Trajectories of the magnetization vector for the first and second spins for the control field represented in the bottom panel. This field is the solution of the homotopy problem for . The red points indicate the possible structure of the solution in terms of bang and singular extremals (see the text).