of neglecting the term representing the contribution of polymer recombination as in this paper we are mainly interested in comparing the early time kinetics of *end evaporation and addition* and *body evaporation and addition*. The early time kinetics is characterised by the lag time, i.e., the time intercept of the tangent at the inflection point of the polymerisation curve, i.e., $M(t)$. [@hellstrand] For the sake of simplicity, we limit ourselves to strongly nucleated polymerisation, and set $k_n^+ \rightarrow 0$. This also reduces the degree of polynomial on the right hand side of Eqs. \[eq6\] and \[eq7\], enabling us to obtain analytical solutions. In the limit $k_n^+ \rightarrow 0$, the polymerisation process has to be seeded, i.e., some initial polymerised mass, $M(0)=P(0) \neq 0$, has to be provided, otherwise the system stays in the initial state $M(0)=P(0)=0$.

![Time evolution of the mean length of the polymer $L(t)=M(t)/P(t)$, obtained by numerically solving Eqs. \[eq6\] and \[eq7\] for two values of recombination rate $\kpf=10^{8}$ and $10^{-8} M s^{-1}$. The remainder of the system parameters are $k_n^+=10^{-5} s^{-1}$, $\kpe=5 \times 10^{5} M^{-1} s^{-1}$, $\kme=10^{-2} s^{-1}$, $\kpb=5 \times 10^{5} M^{-1} s^{-1}$, $\kmb=10^{-2} s^{-1}$, $\kmf=10^{-4} s^{-1}$, $\mtot=10^{-5} M$, $M(0)=\mtot \times 10^{-4}$ and $P(0)=\mtot \times 10^{-6}$, where 