A Prompting-Based Representation Learning Method for Recommendation with Large Language Models
Junyi Chen, Toyotaro Suzumura
TL;DR
This work addresses the challenge of leveraging large language models for recommender systems by introducing P4R, a prompting-based representation learning method. P4R generates informative item profiles via in-context prompting, embeds these profiles with a BERT-based textual encoder, and aligns them with a GCN-based collaborative filtering module using a BPR objective. The proposed framework demonstrates improved ranking metrics on Yelp and Amazon-VideoGames datasets compared to strong GNN baselines, and ablations illustrate the impact of embedding size and prompt design on performance. The approach offers a cost-effective pathway to integrate rich textual context into recommendations, while highlighting limitations around sequential user dynamics and LLM resource requirements.
Abstract
In recent years, Recommender Systems (RS) have witnessed a transformative shift with the advent of Large Language Models (LLMs) in the field of Natural Language Processing (NLP). Models such as GPT-3.5/4, Llama, have demonstrated unprecedented capabilities in understanding and generating human-like text. The extensive information pre-trained by these LLMs allows for the potential to capture a more profound semantic representation from different contextual information of users and items. While the great potential lies behind the thriving of LLMs, the challenge of leveraging user-item preferences from contextual information and its alignment with the improvement of Recommender Systems needs to be addressed. Believing that a better understanding of the user or item itself can be the key factor in improving recommendation performance, we conduct research on generating informative profiles using state-of-the-art LLMs. To boost the linguistic abilities of LLMs in Recommender Systems, we introduce the Prompting-Based Representation Learning Method for Recommendation (P4R). In our P4R framework, we utilize the LLM prompting strategy to create personalized item profiles. These profiles are then transformed into semantic representation spaces using a pre-trained BERT model for text embedding. Furthermore, we incorporate a Graph Convolution Network (GCN) for collaborative filtering representation. The P4R framework aligns these two embedding spaces in order to address the general recommendation tasks. In our evaluation, we compare P4R with state-of-the-art Recommender models and assess the quality of prompt-based profile generation.
