  Although Hinrichsen in his unpublished work theoretically rebutted the
possibility of the discontinuous transition in one-dimensional nonequilibrium
systems unless there are additional conservation laws, long-range interactions,
macroscopic currents, or special boundary conditions, we have recently observed
the resurrection of the claim that the triplet creation model (TC) introduced
by Dickman and Tom\'e [Phys. Rev. E {\bf 44}, 4833 (1991)] would show the
discontinuous transition. By extensive simulations, however, we find that the
one-dimensional TC does belong to the directed percolation universality class
even for larger diffusion constant than the suggested tricritical point in the
literature. Furthermore, we find that the phase boundary is well described by
the crossover from the mean field to the directed percolation, which supports
the claim that the one-dimensional TC does not exhibit a discontinuous
transition.
