FaLW: A Forgetting-aware Loss Reweighting for Long-tailed Unlearning

Fuente: arXiv
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Main Authors: Yu, Liheng, Zhao, Zhe, Wang, Yuxuan, Wang, Pengkun, Cao, Xiaofeng, Wang, Binwu, Wang, Yang
Format: Preprint
Published: 2026
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_version_ 1866911460963123200
author Yu, Liheng
Zhao, Zhe
Wang, Yuxuan
Wang, Pengkun
Cao, Xiaofeng
Wang, Binwu
Wang, Yang
author_facet Yu, Liheng
Zhao, Zhe
Wang, Yuxuan
Wang, Pengkun
Cao, Xiaofeng
Wang, Binwu
Wang, Yang
contents Machine unlearning, which aims to efficiently remove the influence of specific data from trained models, is crucial for upholding data privacy regulations like the ``right to be forgotten". However, existing research predominantly evaluates unlearning methods on relatively balanced forget sets. This overlooks a common real-world scenario where data to be forgotten, such as a user's activity records, follows a long-tailed distribution. Our work is the first to investigate this critical research gap. We find that in such long-tailed settings, existing methods suffer from two key issues: \textit{Heterogeneous Unlearning Deviation} and \textit{Skewed Unlearning Deviation}. To address these challenges, we propose FaLW, a plug-and-play, instance-wise dynamic loss reweighting method. FaLW innovatively assesses the unlearning state of each sample by comparing its predictive probability to the distribution of unseen data from the same class. Based on this, it uses a forgetting-aware reweighting scheme, modulated by a balancing factor, to adaptively adjust the unlearning intensity for each sample. Extensive experiments demonstrate that FaLW achieves superior performance.
format Preprint
id arxiv_https___arxiv_org_abs_2601_18650
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle FaLW: A Forgetting-aware Loss Reweighting for Long-tailed Unlearning
Yu, Liheng
Zhao, Zhe
Wang, Yuxuan
Wang, Pengkun
Cao, Xiaofeng
Wang, Binwu
Wang, Yang
Machine Learning
Artificial Intelligence
Machine unlearning, which aims to efficiently remove the influence of specific data from trained models, is crucial for upholding data privacy regulations like the ``right to be forgotten". However, existing research predominantly evaluates unlearning methods on relatively balanced forget sets. This overlooks a common real-world scenario where data to be forgotten, such as a user's activity records, follows a long-tailed distribution. Our work is the first to investigate this critical research gap. We find that in such long-tailed settings, existing methods suffer from two key issues: \textit{Heterogeneous Unlearning Deviation} and \textit{Skewed Unlearning Deviation}. To address these challenges, we propose FaLW, a plug-and-play, instance-wise dynamic loss reweighting method. FaLW innovatively assesses the unlearning state of each sample by comparing its predictive probability to the distribution of unseen data from the same class. Based on this, it uses a forgetting-aware reweighting scheme, modulated by a balancing factor, to adaptively adjust the unlearning intensity for each sample. Extensive experiments demonstrate that FaLW achieves superior performance.
title FaLW: A Forgetting-aware Loss Reweighting for Long-tailed Unlearning
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2601.18650