xLSTM is more expressive than Transformer, Mamba: arxiv.org/abs/2603.03612
*nonlinear RNNs: sLSTM, LSTM
*DLPR linear RNNs: mLSTM, RWKV-7, DeltaNet
*Non PNC1-complete: Mamba, Transformer
“fundamental expressivity gaps between linear and nonlinear RNNs.”
World models require nonlinear RNNs.
