Efficient Cold-Start Recommendation via BPE Token-Level Embedding Initialization with LLM

Fuente: arXiv
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Main Authors: Zhao, Yushang, Han, Xinyue, Leng, Qian, Sun, Qianyi, Lyu, Haotian, Zhou, Chengrui
Format: Preprint
Published: 2025
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author Zhao, Yushang
Han, Xinyue
Leng, Qian
Sun, Qianyi
Lyu, Haotian
Zhou, Chengrui
author_facet Zhao, Yushang
Han, Xinyue
Leng, Qian
Sun, Qianyi
Lyu, Haotian
Zhou, Chengrui
contents The cold-start issue is the challenge when we talk about recommender systems, especially in the case when we do not have the past interaction data of new users or new items. Content-based features or hybrid solutions are common as conventional solutions, but they can only work in a sparse metadata environment with shallow patterns. In this paper, the efficient cold-start recommendation strategy is presented, which is based on the sub word-level representations by applying Byte Pair Encoding (BPE) tokenization and pre-trained Large Language Model (LLM) embedding in the initialization procedure. We obtain fine-grained token-level vectors that are aligned with the BPE vocabulary as opposed to using coarse-grained sentence embeddings. Together, these token embeddings can be used as dense semantic priors on unseen entities, making immediate recommendation performance possible without user-item interaction history. Our mechanism can be compared to collaborative filtering systems and tested over benchmark datasets with stringent cold-start assumptions. Experimental findings show that the given BPE-LLM method achieves higher Recall@k, NDCG@k, and Hit Rate measurements compared to the standard baseline and displays the same capability of sufficient computational performance. Furthermore, we demonstrate that using subword-aware embeddings yields better generalizability and is more interpretable, especially within a multilingual and sparse input setting. The practical application of token-level semantic initialization as a lightweight, but nevertheless effective extension to modern recommender systems in the zero-shot setting is indicated within this work.
format Preprint
id arxiv_https___arxiv_org_abs_2509_13179
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Efficient Cold-Start Recommendation via BPE Token-Level Embedding Initialization with LLM
Zhao, Yushang
Han, Xinyue
Leng, Qian
Sun, Qianyi
Lyu, Haotian
Zhou, Chengrui
Information Retrieval
Machine Learning
The cold-start issue is the challenge when we talk about recommender systems, especially in the case when we do not have the past interaction data of new users or new items. Content-based features or hybrid solutions are common as conventional solutions, but they can only work in a sparse metadata environment with shallow patterns. In this paper, the efficient cold-start recommendation strategy is presented, which is based on the sub word-level representations by applying Byte Pair Encoding (BPE) tokenization and pre-trained Large Language Model (LLM) embedding in the initialization procedure. We obtain fine-grained token-level vectors that are aligned with the BPE vocabulary as opposed to using coarse-grained sentence embeddings. Together, these token embeddings can be used as dense semantic priors on unseen entities, making immediate recommendation performance possible without user-item interaction history. Our mechanism can be compared to collaborative filtering systems and tested over benchmark datasets with stringent cold-start assumptions. Experimental findings show that the given BPE-LLM method achieves higher Recall@k, NDCG@k, and Hit Rate measurements compared to the standard baseline and displays the same capability of sufficient computational performance. Furthermore, we demonstrate that using subword-aware embeddings yields better generalizability and is more interpretable, especially within a multilingual and sparse input setting. The practical application of token-level semantic initialization as a lightweight, but nevertheless effective extension to modern recommender systems in the zero-shot setting is indicated within this work.
title Efficient Cold-Start Recommendation via BPE Token-Level Embedding Initialization with LLM
topic Information Retrieval
Machine Learning
url https://arxiv.org/abs/2509.13179