PDFs for the dimer concentration at various times. The staircase plots are the results for the discrete case and the continuous lines are the results for the continuous case. Panel A is for the case of constant volume and Panel B is the varying volume case. The parameter values and initial conditions are the same as in Figs. 2 and 4, for the constant volume case and varying volume case, respectively. Each PDF consists of 10, 000 realizations of the process.