arXiv Machine Learning

Expanding Attention: A Taylor-Series Route to Linear-Time Transformers with a Fixed Number of Recurrent States

arXiv:2610. 20637v1 Announce Type: new Abstract: We expand the exponential kernel of attention into a truncated Taylor series of $n$ terms and factorize each term into a tensor-power inner product, which collapses the causal history into exactly $n$ recurrent states, each updated by one rank-one outer product per token and independent of context length $N$.

arXiv Machine Learning
1d ago

Softmax Attention with Any Temperature in Fixed Dimension: Matching the Best Known Maximum-Inner-Product Bounds

arXiv:2611.06055v1 Announce Type: cross Abstract: Attention is central to modern AI models for language, vision, and scientific modeling. However, direct evaluation compares every query with every ke...

By Zixuan Huang (State Key Laboratory of Multimedia Information Processing, School of Computer Science, Peking University, Beijing, China, School of Physics, Peking University, Beijing, China), Guozhang Chen (State Key Laboratory of Multimedia Information Processing, School of Computer Science, Peking University, Beijing, China, National Engineering Research Center of Visual Technology, School of Computer Science, Peking University, Beijing, China)
arXiv Computation and Language
2d ago

Conic Certification of Transformer Attention

The paper introduces a conic programming framework for certifying transformer attention, providing guarantees on how far an attention head’s output can shift under input perturbations. It shows that the main challenge lies in the bilinear interaction between varying queries and keys, making certification NP-hard over boxes and inapproximable when logits can shift by a constant. The authors present an exponential cone moment relaxation that yields a quadratic error bound in the perturbation radius, and demonstrate that this approach outperforms linear bound propagation on GPT‑2, achieving tighter bounds and matching predicted second‑order accuracy.

By Masoud Ataei
arXiv Machine Learning
Jun 9

Token Sample Complexity of Attention

arXiv:2512. 10656v3 Announce Type: replace Abstract: As context windows in large language models continue to expand, it is essential to characterize how attention behaves at extreme sequence lengths.

By L\'ea Bohbot, Cyril Letrouit, Gabriel Peyr\'e, Fran\c{c}ois-Xavier Vialard
arXiv Machine Learning
Sep 22

FlashBoB: I/O-Efficient Exact Backward-over-Backward for Softmax Attention

FlashBoB introduces an I/O‑efficient algorithm for exact backward‑over‑backward (BoB) in softmax attention, enabling precise second‑order differentiation without large intermediate tensors. By exploiting a hierarchical affine structure, the method confines computation to on‑chip tiles and limits off‑chip memory traffic, achieving θ(N² d²/M) HBM usage. Experiments show FlashBoB scales to sequence lengths of 262K on a single A100 GPU, outperforming prior exact baselines and FlashBack by up to 6.3×.

By Anthony Givans, Michael Crawshaw, Mingrui Liu
arXiv Machine Learning
Aug 27

Spectral Allocation: Why Muon Outperforms Adam, and How to Improve Muon

The paper investigates why the orthogonal optimiser Muon outperforms Adam in large language model pretraining by analysing the spectral properties of Transformer loss landscapes. It finds that Muon’s momentum buffers exhibit an anisotropic spectral profile with a volatile head and a tolerant bulk, enabling larger effective step sizes. Building on this insight, the authors propose Spectral‑Aware Muon (SAMuon) and a lightweight variant, which adjust the bulk scaling while keeping the head unchanged, achieving 13–24 % fewer training tokens than Muon without extra FLOPs.

By Xiaodong Wu, Wenyi Yu, Chao Zhang, Philip Woodland