Rethinking the Role of Tensor Decompositions in Post-Training LLM Compression

Artur Zagitov, Alexander Miasnikov, Maxim Krutikov, Artem Tsedenov, Vladimir Aletov, Gleb Molodtsov, Nail Bashirov, Aleksandr Beznosikov


Abstract
Post-training compression is essential for deploying large language models (LLMs) under tight resource constraints. Tensor decompositions have emerged as a promising direction, offering compact parameterizations well suited to Transformer weight structures. However, existing studies evaluate these methods in narrow settings, leaving unclear whether tensorization is effective at large-scale deployment. We systematically evaluate tensor compression across dense and MoE architectures, establishing performance trade-offs grounded in both empirical analysis and theoretical analysis. % We identify a fundamental mismatch between the shared subspaces assumed by tensor decompositions and the heterogeneous representations learned by modern LLMs, thereby delineating their practical limits and clarifying their viable role in large-scale deployment. We identify a fundamental mismatch between the shared subspaces assumed by tensor decompositions and the heterogeneous representations learned by modern LLMs, thereby delineating their practical limits that persist across an extensive range of mainstream dense and MoE deployment settings evaluated in this work. The code is available at https://github.com/brain-lab-research/TT-LLM.
Anthology ID:
2026.emnlp-main.2679
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:
60931–60953
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URL:
https://aclanthology.org/2026.emnlp-main.2679/
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Cite (ACL):
Artur Zagitov, Alexander Miasnikov, Maxim Krutikov, Artem Tsedenov, Vladimir Aletov, Gleb Molodtsov, Nail Bashirov, and Aleksandr Beznosikov. 2026. Rethinking the Role of Tensor Decompositions in Post-Training LLM Compression. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 60931–60953, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Rethinking the Role of Tensor Decompositions in Post-Training LLM Compression (Zagitov et al., EMNLP 2026)
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https://aclanthology.org/2026.emnlp-main.2679.pdf