you can see that this is the v AE bound this is just the variational bound on negative log likelihood so so I guess this is can I ask sorry if you have a stream of let's say oh just lowercase letters A through Z then would P of Z here just be 1 over 26 and then the P of X given Z would be the number of times it occurs in divided by the total length right so it just depends on what your latent variable model happens to be I'm so the case that I'm actually thinking about it is view is that this is a V a and so P of Z is like standard normal