SAE aims to solve the Bilevel optimization problem where the outer optimization minimizes reconstruction error and sparsity regularization, while the inner optimization finds optimal projection values for the encoder given a constraint set.
Duality
Fundamental duality between how concepts are organized in model representations versus how an SAE encoder’s receptive fields should be structured to optimally identify said concepts. Crucially, this implies any SAE is implicitly biased towards identifying concepts that are organized in a specific manner.
The Rate Distortion Dance between reconstruction (Compressed sensing) and sparsity (Interpretable Sparse Coding)