6/ Let X1, X2, ... be i.i.d. integer-valued random variables, and let Sn = _, Xi. Suppose 0 0 so that the conditional probability exists). Hence prove space- and time-homogeneity for the random walk Sn, i.e.: P(Sn = b+ c| Sm = a+c) =P(Sn =b|Sm=a); and P( Sntk = b | Smth = a) = P(Sn = b| Sm = a), again assuming that the relevant conditional probabilities exist