... gives{x(t 1 ) ∈[A 1 , B 1 ], x(t2) ∈[A2, B2], ,x(tN) ∈[AN, BN]} (1. 1.49)=B 1 A 1 dx 1 exp−x2 1 4Dt 1 √4π Dt 1 B2A2dx2exp−(x2−x 1 )24D(t2−t 1 )√4π ... (1. 1.50) and (1. 1. 51) ) from the points x(ti 1 ) to the next positions x (ti) in the sequence:{0,0;t }dWx(τ ) χY[x(τ );x 1 , ,xN]=Ni =1 W (xi, ti|xi 1 , ti 1 )=Ni =1 14π ... δi0, then equations (1. 1 .13 ) and (1. 1.8)give for the evolution of the distributionwi(n) =0 if |i| > n or (i + n) is odd 1 2nn 1 2(n + i)if |i|≤n and (i + n) is even. (1. 1 .14 )Making...