When the connections are time-independent rate constants, the master equation represents a kinetic scheme, and the process is Markovian (any jumping time probability density function for state i is an exponential, with a rate equal to the value of the connection). When the connections depend on the actual time (i.e. matrix A depends on the time, A → → A ( t ) ), the process is not stationary and the master equation reads d P → → d t = A ( t ) P → → .