Before it
Attention's quadratic cost was treated as the price of good sequence modelling.
The problem
State-space models scale linearly but could not match transformers on language.
What it introduced
Make the state-space parameters input-dependent, so the model can selectively remember or forget, with a hardware-aware scan.
Why it matters
The strongest challenger to attention so far. Frontier models remain transformers, so treat this as a live parallel branch.
What modern models inherit
An open question about whether attention is the final answer.
What came next
Mamba-2 and hybrid attention-SSM architectures.