when we see here if then the cost of transmitting data is not a is a little higher than log 1 over P of X because effectively we have the wrong distribution here we have Q instead of P this is the evidence lower bound we applies with the BAE so if you use a via e to do bits back coding by optimizing the loss of the VA e there directly optimizing the compression capability of this big back coding approach so perfect match between the VA objective and compression so how about that source of random bits that we also like to send