Unlocking Efficient, Scalable, and Continual Knowledge Editing with Basis-Level Representation Fine-Tuning

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Hauptverfasser: Liu, Tianci, Li, Ruirui, Qi, Yunzhe, Liu, Hui, Tang, Xianfeng, Zheng, Tianqi, Yin, Qingyu, Cheng, Monica Xiao, Huan, Jun, Wang, Haoyu, Gao, Jing
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Veröffentlicht: 2025
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author Liu, Tianci
Li, Ruirui
Qi, Yunzhe
Liu, Hui
Tang, Xianfeng
Zheng, Tianqi
Yin, Qingyu
Cheng, Monica Xiao
Huan, Jun
Wang, Haoyu
Gao, Jing
author_facet Liu, Tianci
Li, Ruirui
Qi, Yunzhe
Liu, Hui
Tang, Xianfeng
Zheng, Tianqi
Yin, Qingyu
Cheng, Monica Xiao
Huan, Jun
Wang, Haoyu
Gao, Jing
contents Large language models (LLMs) have achieved remarkable performance on various natural language tasks. However, they are trained on static corpora and their knowledge can become outdated quickly in the fast-changing world. This motivates the development of knowledge editing methods designed to update certain knowledge in LLMs without changing unrelated others. To make selective edits, previous efforts often sought to update a small amount of parameters in some specific layer(s) of a LLM. Nonetheless, in challenging scenarios, they still fall short in making successful edits while preserving knowledge irrelevant to the updates simultaneously, resulting in a notable editing-locality trade-off. In this work, we question if the trade-offs are caused by the fact that parameter-based updates have a global effect, i.e., edited parameters affect all inputs indiscriminately. In light of this, we explore the feasibility of representation fine-tuning, which applied some linear update to a few representations in a learned subspace, for knowledge editing. While being effective to enhance an LLM's general ability as demonstrated in the previous work, we theoretically show that this linear update imposes a tension in editing-locality trade-off. Subsequently, BaFT is proposed to break the linearity. BaFT computes a weight for each basis that spans a dimension of the subspace based on the input representation. This input-dependent weighting mechanism allows BaFT to manage different types of knowledge in an adaptive way, thereby achieving a better editing-locality trade-off. Experiments on three LLMs with five editing benchmarks in diverse scenarios show the superiority of our method.
format Preprint
id arxiv_https___arxiv_org_abs_2503_00306
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Unlocking Efficient, Scalable, and Continual Knowledge Editing with Basis-Level Representation Fine-Tuning
Liu, Tianci
Li, Ruirui
Qi, Yunzhe
Liu, Hui
Tang, Xianfeng
Zheng, Tianqi
Yin, Qingyu
Cheng, Monica Xiao
Huan, Jun
Wang, Haoyu
Gao, Jing
Computation and Language
Machine Learning
Large language models (LLMs) have achieved remarkable performance on various natural language tasks. However, they are trained on static corpora and their knowledge can become outdated quickly in the fast-changing world. This motivates the development of knowledge editing methods designed to update certain knowledge in LLMs without changing unrelated others. To make selective edits, previous efforts often sought to update a small amount of parameters in some specific layer(s) of a LLM. Nonetheless, in challenging scenarios, they still fall short in making successful edits while preserving knowledge irrelevant to the updates simultaneously, resulting in a notable editing-locality trade-off. In this work, we question if the trade-offs are caused by the fact that parameter-based updates have a global effect, i.e., edited parameters affect all inputs indiscriminately. In light of this, we explore the feasibility of representation fine-tuning, which applied some linear update to a few representations in a learned subspace, for knowledge editing. While being effective to enhance an LLM's general ability as demonstrated in the previous work, we theoretically show that this linear update imposes a tension in editing-locality trade-off. Subsequently, BaFT is proposed to break the linearity. BaFT computes a weight for each basis that spans a dimension of the subspace based on the input representation. This input-dependent weighting mechanism allows BaFT to manage different types of knowledge in an adaptive way, thereby achieving a better editing-locality trade-off. Experiments on three LLMs with five editing benchmarks in diverse scenarios show the superiority of our method.
title Unlocking Efficient, Scalable, and Continual Knowledge Editing with Basis-Level Representation Fine-Tuning
topic Computation and Language
Machine Learning
url https://arxiv.org/abs/2503.00306