Erase at the Core: Representation Unlearning for Machine Unlearning

Fuente: arXiv
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Main Authors: Lee, Jaewon, Kim, Yongwoo, Kim, Donghyun
Format: Preprint
Published: 2026
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author Lee, Jaewon
Kim, Yongwoo
Kim, Donghyun
author_facet Lee, Jaewon
Kim, Yongwoo
Kim, Donghyun
contents Many approximate machine unlearning methods demonstrate strong logit-level forgetting -- such as near-zero accuracy on the forget set -- yet continue to preserve substantial information within their internal feature representations. We refer to this discrepancy as superficial forgetting. Recent studies indicate that most existing unlearning approaches primarily alter the final classifier, leaving intermediate representations largely unchanged and highly similar to those of the original model. To address this limitation, we introduce the Erase at the Core (EC), a framework designed to enforce forgetting throughout the entire network hierarchy. EC integrates multi-layer contrastive unlearning on the forget set with retain set preservation through deeply supervised learning. Concretely, EC attaches auxiliary modules to intermediate layers and applies both contrastive unlearning and cross-entropy losses at each supervision point, with layer-wise weighted losses. Experimental results show that EC not only achieves effective logit-level forgetting, but also substantially reduces representational similarity to the original model across intermediate layers. Furthermore, EC is model-agnostic and can be incorporated as a plug-in module into existing unlearning methods, improving representation-level forgetting while maintaining performance on the retain set.
format Preprint
id arxiv_https___arxiv_org_abs_2602_05375
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Erase at the Core: Representation Unlearning for Machine Unlearning
Lee, Jaewon
Kim, Yongwoo
Kim, Donghyun
Machine Learning
Computer Vision and Pattern Recognition
Many approximate machine unlearning methods demonstrate strong logit-level forgetting -- such as near-zero accuracy on the forget set -- yet continue to preserve substantial information within their internal feature representations. We refer to this discrepancy as superficial forgetting. Recent studies indicate that most existing unlearning approaches primarily alter the final classifier, leaving intermediate representations largely unchanged and highly similar to those of the original model. To address this limitation, we introduce the Erase at the Core (EC), a framework designed to enforce forgetting throughout the entire network hierarchy. EC integrates multi-layer contrastive unlearning on the forget set with retain set preservation through deeply supervised learning. Concretely, EC attaches auxiliary modules to intermediate layers and applies both contrastive unlearning and cross-entropy losses at each supervision point, with layer-wise weighted losses. Experimental results show that EC not only achieves effective logit-level forgetting, but also substantially reduces representational similarity to the original model across intermediate layers. Furthermore, EC is model-agnostic and can be incorporated as a plug-in module into existing unlearning methods, improving representation-level forgetting while maintaining performance on the retain set.
title Erase at the Core: Representation Unlearning for Machine Unlearning
topic Machine Learning
Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2602.05375