Assume that you have a matrix $X$ and you want to project it onto a subspace by using PCA. It will work. Then you are trying to use a linear autoencoder to projecting $X$ onto the same subspace. It will work too.
Question:
Assume that the PCA projection has $c$ components. Can a linear autoencoder project $X$ onto the subspace with the same results as PCA does, with layers $l$ that are less then components $c$?
My goal here is to create a linear autoencoder that can perform the same results, with less layers than components.