Long-Chain Reasoning Distillation via Adaptive Prefix Alignment

Fuente: arXiv
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Main Authors: Liu, Zhenghao, Wu, Zhuoyang, Li, Xinze, Yan, Yukun, Wang, Shuo, Chen, Zulong, Gu, Yu, Yu, Ge, Sun, Maosong
Format: Preprint
Published: 2026
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author Liu, Zhenghao
Wu, Zhuoyang
Li, Xinze
Yan, Yukun
Wang, Shuo
Chen, Zulong
Gu, Yu
Yu, Ge
Sun, Maosong
author_facet Liu, Zhenghao
Wu, Zhuoyang
Li, Xinze
Yan, Yukun
Wang, Shuo
Chen, Zulong
Gu, Yu
Yu, Ge
Sun, Maosong
contents Large Language Models (LLMs) have demonstrated remarkable reasoning capabilities, particularly in solving complex mathematical problems. Recent studies show that distilling long reasoning trajectories can effectively enhance the reasoning performance of small-scale student models. However, teacher-generated reasoning trajectories are often excessively long and structurally complex, making them difficult for student models to learn. This mismatch leads to a gap between the provided supervision signal and the learning capacity of the student model. To address this challenge, we propose Prefix-ALIGNment distillation (P-ALIGN), a framework that fully exploits teacher CoTs for distillation through adaptive prefix alignment. Specifically, P-ALIGN adaptively truncates teacher-generated reasoning trajectories by determining whether the remaining suffix is concise and sufficient to guide the student model. Then, P-ALIGN leverages the teacher-generated prefix to supervise the student model, encouraging effective prefix alignment. Experiments on multiple mathematical reasoning benchmarks demonstrate that P-ALIGN outperforms all baselines by over 3%. Further analysis indicates that the prefixes constructed by P-ALIGN provide more effective supervision signals, while avoiding the negative impact of redundant and uncertain reasoning components. All code is available at https://github.com/NEUIR/P-ALIGN.
format Preprint
id arxiv_https___arxiv_org_abs_2601_10064
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Long-Chain Reasoning Distillation via Adaptive Prefix Alignment
Liu, Zhenghao
Wu, Zhuoyang
Li, Xinze
Yan, Yukun
Wang, Shuo
Chen, Zulong
Gu, Yu
Yu, Ge
Sun, Maosong
Computation and Language
Large Language Models (LLMs) have demonstrated remarkable reasoning capabilities, particularly in solving complex mathematical problems. Recent studies show that distilling long reasoning trajectories can effectively enhance the reasoning performance of small-scale student models. However, teacher-generated reasoning trajectories are often excessively long and structurally complex, making them difficult for student models to learn. This mismatch leads to a gap between the provided supervision signal and the learning capacity of the student model. To address this challenge, we propose Prefix-ALIGNment distillation (P-ALIGN), a framework that fully exploits teacher CoTs for distillation through adaptive prefix alignment. Specifically, P-ALIGN adaptively truncates teacher-generated reasoning trajectories by determining whether the remaining suffix is concise and sufficient to guide the student model. Then, P-ALIGN leverages the teacher-generated prefix to supervise the student model, encouraging effective prefix alignment. Experiments on multiple mathematical reasoning benchmarks demonstrate that P-ALIGN outperforms all baselines by over 3%. Further analysis indicates that the prefixes constructed by P-ALIGN provide more effective supervision signals, while avoiding the negative impact of redundant and uncertain reasoning components. All code is available at https://github.com/NEUIR/P-ALIGN.
title Long-Chain Reasoning Distillation via Adaptive Prefix Alignment
topic Computation and Language
url https://arxiv.org/abs/2601.10064