Efficient Utility-Preserving Machine Unlearning with Implicit Gradient Surgery

Fuente: arXiv
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Main Authors: Zhou, Shiji, Yu, Tianbai, Zhang, Zhi, Chang, Heng, Zhou, Xiao, Wu, Dong, Zhao, Han
Format: Preprint
Published: 2025
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author Zhou, Shiji
Yu, Tianbai
Zhang, Zhi
Chang, Heng
Zhou, Xiao
Wu, Dong
Zhao, Han
author_facet Zhou, Shiji
Yu, Tianbai
Zhang, Zhi
Chang, Heng
Zhou, Xiao
Wu, Dong
Zhao, Han
contents Machine unlearning (MU) aims to efficiently remove sensitive or harmful memory from a pre-trained model. The key challenge is to balance the potential tradeoff between unlearning efficacy and utility preservation, which involves forgetting undesirable information as defined while maintaining the model's original performance. One potential way to tackle this problem is to use multi-objective optimization to jointly optimize both the unlearning and utility preservation objectives. However, existing multi-objective methods only guarantee finding a Pareto-optimal solution without fine-grained control, which causes under-optimization of the unlearning objective. To this end, we first model MU as a constrained optimization problem, that is, optimizing the unlearning objective under the constraint of a bounded increase for utility loss. We then show that solving this optimization problem is equivalent to unilateral gradient surgery on the unlearning objective. To resolve the additional computational cost brought by gradient surgery, we propose an implicit gradient surgery method, which approximates the solution to the aforementioned constrained optimization problem via only one backpropagation, thereby achieving efficient utility-preserving MU. Theoretically, we provide a tight convergence analysis of the algorithm. Empirically, our extensive experiments show that the proposed algorithm achieves better tradeoff results than existing baselines. Codes are available at https://github.com/anseryuer/EUPMU-Efficient-Utility-Preserving-Machine-Unlearning.
format Preprint
id arxiv_https___arxiv_org_abs_2510_22124
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Efficient Utility-Preserving Machine Unlearning with Implicit Gradient Surgery
Zhou, Shiji
Yu, Tianbai
Zhang, Zhi
Chang, Heng
Zhou, Xiao
Wu, Dong
Zhao, Han
Machine Learning
Artificial Intelligence
Machine unlearning (MU) aims to efficiently remove sensitive or harmful memory from a pre-trained model. The key challenge is to balance the potential tradeoff between unlearning efficacy and utility preservation, which involves forgetting undesirable information as defined while maintaining the model's original performance. One potential way to tackle this problem is to use multi-objective optimization to jointly optimize both the unlearning and utility preservation objectives. However, existing multi-objective methods only guarantee finding a Pareto-optimal solution without fine-grained control, which causes under-optimization of the unlearning objective. To this end, we first model MU as a constrained optimization problem, that is, optimizing the unlearning objective under the constraint of a bounded increase for utility loss. We then show that solving this optimization problem is equivalent to unilateral gradient surgery on the unlearning objective. To resolve the additional computational cost brought by gradient surgery, we propose an implicit gradient surgery method, which approximates the solution to the aforementioned constrained optimization problem via only one backpropagation, thereby achieving efficient utility-preserving MU. Theoretically, we provide a tight convergence analysis of the algorithm. Empirically, our extensive experiments show that the proposed algorithm achieves better tradeoff results than existing baselines. Codes are available at https://github.com/anseryuer/EUPMU-Efficient-Utility-Preserving-Machine-Unlearning.
title Efficient Utility-Preserving Machine Unlearning with Implicit Gradient Surgery
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2510.22124