Kronecker Factorization Improves Efficiency and Interpretability of Sparse Autoencoders

Vadim Kurochkin, Yaroslav Aksenov, Daniil Laptev, Daniil Gavrilov, Nikita Balagansky


Abstract
Sparse Autoencoders (SAEs) decompose language-model activations into sparse, interpretable features, but standard encoders usually treat the latent dictionary as a flat set of independent coordinates, leaving hierarchy and feature interactions to emerge only implicitly. We propose KronSAE, a design that factorizes the latent space into heads and forms post-latent features as pairwise compositions of lower-dimensional pre-latents using mAND, a differentiable AND-like interaction. This imposes a compositional co-activation prior while remaining compatible with standard SAE objectives and variants such as TopK, Matryoshka, and Switch SAEs. KronSAE matches strong baselines on the EV–FLOPs frontier, improves interpretability of the latents, better captures the underlying correlated feature structure, and reduces encoder computational cost as an additional benefit. Code is available at https://github.com/corl-team/kronsae.
Anthology ID:
2026.emnlp-main.2480
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
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Pages:
56302–56323
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URL:
https://aclanthology.org/2026.emnlp-main.2480/
DOI:
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Cite (ACL):
Vadim Kurochkin, Yaroslav Aksenov, Daniil Laptev, Daniil Gavrilov, and Nikita Balagansky. 2026. Kronecker Factorization Improves Efficiency and Interpretability of Sparse Autoencoders. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 56302–56323, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Kronecker Factorization Improves Efficiency and Interpretability of Sparse Autoencoders (Kurochkin et al., EMNLP 2026)
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https://aclanthology.org/2026.emnlp-main.2480.pdf