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Main Authors: Li, Shaoang, Shi, Yanhang, Li, Yufei, Liang, Mingfu, Wei, Xiaohan, Pu, Yunchen, Tian, Fei, Sun, Chonglin, Shyu, Frank, Simon, Luke, Pandey, Sandeep, Liu, Xi, Li, Jian
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2604.22565
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author Li, Shaoang
Shi, Yanhang
Li, Yufei
Liang, Mingfu
Wei, Xiaohan
Pu, Yunchen
Tian, Fei
Sun, Chonglin
Shyu, Frank
Simon, Luke
Pandey, Sandeep
Liu, Xi
Li, Jian
author_facet Li, Shaoang
Shi, Yanhang
Li, Yufei
Liang, Mingfu
Wei, Xiaohan
Pu, Yunchen
Tian, Fei
Sun, Chonglin
Shyu, Frank
Simon, Luke
Pandey, Sandeep
Liu, Xi
Li, Jian
contents Large Language Models (LLMs) can reason well, yet often miss decisive evidence when it is buried in long, noisy contexts. We introduce HiLight, an Evidence Emphasis framework that decouples evidence selection from reasoning for frozen LLM solvers. HiLight avoids compressing or rewriting the input, which can discard or distort evidence, by training a lightweight Emphasis Actor to insert minimal highlight tags around pivotal spans in the unaltered context. A frozen Solver then performs downstream reasoning on the emphasized input. We cast highlighting as a weakly supervised decision-making problem and optimize the Actor with reinforcement learning using only the Solver's task reward, requiring no evidence labels and no access to or modification of the Solver. Across sequential recommendation and long-context question answering, HiLight consistently improves performance over strong prompt-based and automated prompt-optimization baselines. The learned emphasis policy transfers zero-shot to both smaller and larger unseen Solver families, including an API-based Solver, suggesting that the Actor captures genuine, reusable evidence structure rather than overfitting to a single backbone.
format Preprint
id arxiv_https___arxiv_org_abs_2604_22565
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Learning Evidence Highlighting for Frozen LLMs
Li, Shaoang
Shi, Yanhang
Li, Yufei
Liang, Mingfu
Wei, Xiaohan
Pu, Yunchen
Tian, Fei
Sun, Chonglin
Shyu, Frank
Simon, Luke
Pandey, Sandeep
Liu, Xi
Li, Jian
Computation and Language
Artificial Intelligence
Large Language Models (LLMs) can reason well, yet often miss decisive evidence when it is buried in long, noisy contexts. We introduce HiLight, an Evidence Emphasis framework that decouples evidence selection from reasoning for frozen LLM solvers. HiLight avoids compressing or rewriting the input, which can discard or distort evidence, by training a lightweight Emphasis Actor to insert minimal highlight tags around pivotal spans in the unaltered context. A frozen Solver then performs downstream reasoning on the emphasized input. We cast highlighting as a weakly supervised decision-making problem and optimize the Actor with reinforcement learning using only the Solver's task reward, requiring no evidence labels and no access to or modification of the Solver. Across sequential recommendation and long-context question answering, HiLight consistently improves performance over strong prompt-based and automated prompt-optimization baselines. The learned emphasis policy transfers zero-shot to both smaller and larger unseen Solver families, including an API-based Solver, suggesting that the Actor captures genuine, reusable evidence structure rather than overfitting to a single backbone.
title Learning Evidence Highlighting for Frozen LLMs
topic Computation and Language
Artificial Intelligence
url https://arxiv.org/abs/2604.22565