Fig. The approximation to rate of product formation (71) in time. The solid black curve is the numerical solution of k 2 c 1 , and the dashed/dotted curve corresponds to the numerical solution of k 4 c 2 . The dashed vertical line corresponds to the lag time t * * s 2 . Time has been mapped to the t∞ scale: t∞(t) = 1 -1/ ln(t + e).