architectures there's under complete and over complete so what angela has just described to you is an under complete architecture so remember what she said is that we're trying to find the underlying pattern within our input but to do that what we need to do is to ensure that the neurons within our hidden layer are less than the neurons within our input layer to ensure that whatever our reconstruction of our output is it's not a direct copy of the input then it didn't learn the underlying pattern it needs to be a