arXiv Machine Learning

The Sirens' Song: When Proximal Background Context Overshadows Distant Evidence

The paper introduces the Proximity Trap, a problem where long-context language models fail to attend to distant evidence because of competition from abundant, irrelevant proximal background. To mitigate this, the authors propose LYRA, a t‑distributed directional matching mechanism that reshapes the retrieval distribution to focus more on task‑relevant evidence while preserving positional information. Experiments on LongBench‑v2, RULER, and LongBench show consistent performance gains, and a new benchmark, ProxBench, is presented to evaluate distant evidence usage under varying proximal interference.

arXiv AI
Jun 30

MATCH: Modulating Attention via In-Context Retrieval for Long-Context Transformers

arXiv:2606. 29844v1 Announce Type: cross Abstract: The quadratic computational cost of traditional attention mechanisms poses a major bottleneck to the scalability and practical deployment of large language models (LLMs), particularly in long-context scenarios.

By Linrui Ma, Chun Hei Lo, Xinyu Wang, Peng Lu, Xihao Yuan, Hanting Chen, Kai Han, Xinghao Chen, Chengjun Zhan, Hanlin Xu, Yichun Yin, Lifeng Shang, Feng Wen, Boxing Chen, Yufei Cui
arXiv Machine Learning
Oct 9

Remember to Forget: Gated Adaptive Positional Encoding

The paper introduces GAPE (Gated Adaptive Positional Encoding), a drop‑in augmentation for rotary positional encodings that adds content‑aware bias to attention logits while preserving rotary geometry. GAPE uses a query‑dependent gate to contract irrelevant context and a key‑dependent gate to keep salient distant tokens, leading to exponential attenuation of weakly protected context. Experiments show that GAPE improves long‑context robustness, extrapolating up to eight times the training length, and can be retrofitted into a pretrained 7B model without losing benchmark performance.

By Riccardo Ali, Alessio Borgi, Mario Severino, Pietro Li\`o, Christopher Irwin
arXiv AI
5d ago

Head Dimension Matters in Language Models for Long-Context Retrieval

The paper investigates how the dimension of attention heads influences long‑context retrieval in language models. Experiments show that while pretraining loss and short‑context tasks are largely unaffected, wider heads significantly improve retrieval performance at fixed model sizes. Ablation studies indicate that this benefit persists even when attention weights are frozen, suggesting that wider heads enhance adaptation of other model components such as embeddings and MLPs.

By Seiya Tokui, Shoichiro Yamaguchi, Sosuke Kobayashi
arXiv Computation and Language
Sep 1

Where Does Long-Context Supervision Actually Go? Effective-Context Exposure Balancing

The paper introduces EXACT, a supervision-allocation objective that reweights long-context targets by inverse frequency to address a token-level supervision mismatch in packed training. Across seven Qwen/LLaMA configurations, EXACT consistently improves NoLiMa and RULER metrics, with notable gains on Qwen2.5-0.5B and LLaMA-3.2-3B. Standard QA and reasoning performance remain largely unchanged, and a distance-resolved probe shows benefits primarily when evidence is thousands of tokens away.

By Jinchang Zhu, Jindong Li, Chengyu Zou, Rong Fu, Chao Wang, Haowei He, Menglin Yang
arXiv AI
Jul 8

LongCrafter: Towards Diverse Long-Context Understanding via Evidence-Graph-Guided Instruction Synthesis

arXiv:2607. 06160v1 Announce Type: cross Abstract: Synthesizing long-context supervised fine-tuning (SFT) data is a scalable way to enhance the long-context understanding of large language models (LLMs), yet existing approaches share three limitations: narrow task coverage, insufficient instruction difficulty, and a lack of faithfulness supervision.

By Chenhao Yuan, Yinhao Xu, Shuwen Xu, Xizhi Yang, Jiaxiang Liu, Chenxi Zhou, Shaoping Huang, Haolin Ren, Pengfei Cao, Jun Zhao, Kang Liu