are 750, 1500, and 400 for the data in the active, critical, and absorbing phases, respectively. The flatness of $\rho_p(t) t^{\delta}$ over four log decades in time confirms the solid DP critical scaling of the PCP.

At finite $w$, the model still belongs to the DP class irrespective of $q$. Unlike the PCPD to the DP crossover model in Ref. [@PP06], however, the critical lines show two completely different singular behaviors, depending on the value of $q$. For large $q$, the activity of the system is enhanced by additional single-particle reaction processes (excitatory process) and the system becomes overly activated even with infinitesimal $w$. The critical line does not converge to the PCP critical point as $w$ decreases to zero ($w=0^+$) and shows a discontinuous jump. On the other hand, for small $q$, the system activity is suppressed (inhibitory process) and the system becomes more inactive. The critical line nicely converges to the PCP critical point and shows a continuous crossover with a nontrivial crossover exponent.

![\[Fig:PCP\_pc\] (Color online) Semilogarithmic plot of $\rho_p(t) t^{\delta}$ vs $t$ of the PCP near criticality with $\delta = 0.1595$ to be the exponent of the DP. Since the upper (lower) curve veers up (down), 