Hi, I have a (markov chain) transition matrix X which I understand. In particular each row of this matrix sums to 1. I have used this transition matrix to construct it's generator, Y. I.e. Y is the continuously compounded transition matrix, X = exp(Y) X*X = exp(2Y), etc both X and Y are matrices. I am told that the sums of Y must sum to 0, but I can not see why this should be the case. Is it obvious? Many Thanks.