Abstract
An exact markovian master equation for the smoothed classical distribution function f̄ =Mfis derived using the existence of the operator [1 +M(−1 + exp (‐it L))]−1. It is shown that according to the information theory f̄0= 0 (“initial random phase approximation”) should be taken. Then in the first order of a perturbation approach the master equation given by POMPE and VOSS can be derived in the long time approximation.