DAS finds number- and unit-specific quantity-comparison subspaces

Sasaki et al. use Distributed Alignment Search (1024 intervention dimensions, 512 per variable) to locate linear subspaces aligned with a NumLogDiff and a UnitLogDiff variable in quantity-comparison activations [sasaki-etal-2026-language-models-compare-quantities-using-number-specific-and-unit-specific-heuristics] Interchange Intervention Accuracy exceeds 0.9 in many middle layers versus near-chance baselines [sasaki-etal-2026-language-models-compare-quantities-using-number-specific-and-unit-specific-heuristics] A linear surrogate over these variables predicts the model's comparison preference at R^2 approximately 0.817 overall (0.763 near the decision boundary) for Qwen3-4B-Base [sasaki-etal-2026-language-models-compare-quantities-using-number-specific-and-unit-specific-heuristics] This supports a "bag of number-specific and unit-specific heuristics" account over exact-scale unit conversion [sasaki-etal-2026-language-models-compare-quantities-using-number-specific-and-unit-specific-heuristics]