Even TC0-safe state-tracking tasks: Transformers generalize worse than linear RNNs

jowenpetty · x · 2026-11-04

Allen AI researchers concede Transformers are contained in TC0 (or stricter depending on the attention model), but the paper's key takeaway is that even for state-tracking tasks solidly inside TC0, Transformers show worse generalization than linear RNNs. Accompanying figures map architectures onto the state-tracking complexity hierarchy (AC0/TC0/NC1) and show GDNs generalize perfectly on r-trivial, aperiodic and solvable data, while Transformers fail beyond their training distribution and even struggle in-distribution on general finite data.

Related event: Ai2's StateBench: frontier models drop below 13% on long-context state tracking(18 posts)→

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