BEAR: Towards Beam-Search-Aware Optimization for Recommendation with Large Language Models

Fuente: arXiv
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Hauptverfasser: Yang, Weiqin, Wang, Bohao, Xu, Zhenxiang, Chen, Jiawei, Zhang, Shengjia, Chen, Jingbang, Jin, Canghong, Wang, Can
Format: Preprint
Veröffentlicht: 2026
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author Yang, Weiqin
Wang, Bohao
Xu, Zhenxiang
Chen, Jiawei
Zhang, Shengjia
Chen, Jingbang
Jin, Canghong
Wang, Can
author_facet Yang, Weiqin
Wang, Bohao
Xu, Zhenxiang
Chen, Jiawei
Zhang, Shengjia
Chen, Jingbang
Jin, Canghong
Wang, Can
contents Recent years have seen a rapid surge in research leveraging Large Language Models (LLMs) for recommendation. These methods typically employ supervised fine-tuning (SFT) to adapt LLMs to recommendation scenarios, and utilize beam search during inference to efficiently retrieve $B$ top-ranked recommended items. However, we identify a critical training-inference inconsistency: while SFT optimizes the overall probability of positive items, it does not guarantee that such items will be retrieved by beam search even if they possess high overall probabilities. Due to the greedy pruning mechanism, beam search can prematurely discard a positive item once its prefix probability is insufficient. To address this inconsistency, we propose BEAR (Beam-SEarch-Aware Regularization), a novel fine-tuning objective that explicitly accounts for beam search behavior during training. Rather than directly simulating beam search for each instance during training, which is computationally prohibitive, BEAR enforces a relaxed necessary condition: each token in a positive item must rank within the top-$B$ candidate tokens at each decoding step. This objective effectively mitigates the risk of incorrect pruning while incurring negligible computational overhead compared to standard SFT. Extensive experiments across four real-world datasets demonstrate that BEAR significantly outperforms strong baselines. Code is available at https://github.com/Tiny-Snow/BEAR-SIGIR-2026 .
format Preprint
id arxiv_https___arxiv_org_abs_2601_22925
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle BEAR: Towards Beam-Search-Aware Optimization for Recommendation with Large Language Models
Yang, Weiqin
Wang, Bohao
Xu, Zhenxiang
Chen, Jiawei
Zhang, Shengjia
Chen, Jingbang
Jin, Canghong
Wang, Can
Information Retrieval
Artificial Intelligence
Machine Learning
Recent years have seen a rapid surge in research leveraging Large Language Models (LLMs) for recommendation. These methods typically employ supervised fine-tuning (SFT) to adapt LLMs to recommendation scenarios, and utilize beam search during inference to efficiently retrieve $B$ top-ranked recommended items. However, we identify a critical training-inference inconsistency: while SFT optimizes the overall probability of positive items, it does not guarantee that such items will be retrieved by beam search even if they possess high overall probabilities. Due to the greedy pruning mechanism, beam search can prematurely discard a positive item once its prefix probability is insufficient. To address this inconsistency, we propose BEAR (Beam-SEarch-Aware Regularization), a novel fine-tuning objective that explicitly accounts for beam search behavior during training. Rather than directly simulating beam search for each instance during training, which is computationally prohibitive, BEAR enforces a relaxed necessary condition: each token in a positive item must rank within the top-$B$ candidate tokens at each decoding step. This objective effectively mitigates the risk of incorrect pruning while incurring negligible computational overhead compared to standard SFT. Extensive experiments across four real-world datasets demonstrate that BEAR significantly outperforms strong baselines. Code is available at https://github.com/Tiny-Snow/BEAR-SIGIR-2026 .
title BEAR: Towards Beam-Search-Aware Optimization for Recommendation with Large Language Models
topic Information Retrieval
Artificial Intelligence
Machine Learning
url https://arxiv.org/abs/2601.22925