it's been studied you know a lot one thing that is not yet studied is what if you make the decoder nonlinear let's say instead of having a matrix here that you multiply Z by you have an entire neural net what happens I'll tell you about this little bit later now here is the problem though finding you know finding I'm sorry it's not what I wanted to show finding Z for a given X a pair X Y finding the Z that minimizes the sum of those two terms can be expensive you have to back popping equation today is to go in and decide this could be a non