Table 1 Estimated parameter values of the S-system model of the pathway in Figure 2 using log(SSE) < -7 as termination criterion. ^a Regressor: A: all variables used as regressors and subsequently constrained; B: use of "union" variables as regressors (see Text); C: fully informed selection of regressors (see Text). ^b time (secs) needed to converge to the solution with log(SSE) < -7. ^c Convergence results according to AR algorithm: *: convergence to the true solution; **: convergence to different solution; ***: no convergence. ^d time after running 1,000,000 iterations. See Eq. (12) for optimal parameter values and the Additional file for further comments.

α _i

g _{i 1}

g _{i 2}

g _{i 3}

g _{i 4}

β _i

h _{i 1}

h _{i 2}

h _{i 3}

h _{i 4}

log(SSE)

Time(sec)^b

Note^c