Log–log plot of the time courses of the survival
probability obtained in computer simulations of random walk on the
Sierpiński gasket limited to the cluster of the 9th order and for
all walkers starting from a set of 33 = 27 sites, each at
the beginning occupied with the same probability equal to 1/27, and
composing simultaneously the gate to exit the lattice. The value of the
ratio q = 0.1 was assumed for all gate sites. Time
is measured by the number of steps in which transitions were randomly
generated. Curve a is for the gate preserving the
self-similarity symmetry of the lattice. Starting from the value
logt = 3, this curve is practically identical to
that obtained for the cluster of the 6th order in the presence of the
single site gate, translated by ∼2.05 logarithmic units (cf. Fig. 3,
curves for r = 6 and 9) and, thus, for the
effective value of q ≈ 102.05 ×
0.1 ≈ 11.2. Curve b is for the gate colinearly
extended to the maximum. Note a larger value of the exponent α also
in the power-law stage of the reaction.