Graph Unlearning Meets Influence-aware Negative Preference Optimization
Qiang Chen, Zhongze Wu, Ang He, Xi Lin, Shuo Jiang, Shan You, Chang Xu, Yi Chen, Xiu Su
TL;DR
The paper tackles graph unlearning by reframing edge forgetting as a negative preference optimization task and addressing topological coupling that degrades model utility during unlearning. It introduces INPO, which combines an influence-aware message passing scheme, a fast edge-influence estimator, and a topological entropy loss, forming the holistic objective $Loss = \lambda_1 L_{NPO} + \lambda_2 L_{GD} + \lambda_3 TE$. Empirical results on five real-world datasets show that INPO achieves state-of-the-art forget quality while preserving utility, with ablations confirming the contribution of each component. The work advances practical graph unlearning by delivering robust forgetting under varying deletion scenarios and provides code to enable reproducibility and wider adoption.
Abstract
Recent advancements in graph unlearning models have enhanced model utility by preserving the node representation essentially invariant, while using gradient ascent on the forget set to achieve unlearning. However, this approach causes a drastic degradation in model utility during the unlearning process due to the rapid divergence speed of gradient ascent. In this paper, we introduce \textbf{INPO}, an \textbf{I}nfluence-aware \textbf{N}egative \textbf{P}reference \textbf{O}ptimization framework that focuses on slowing the divergence speed and improving the robustness of the model utility to the unlearning process. Specifically, we first analyze that NPO has slower divergence speed and theoretically propose that unlearning high-influence edges can reduce impact of unlearning. We design an influence-aware message function to amplify the influence of unlearned edges and mitigate the tight topological coupling between the forget set and the retain set. The influence of each edge is quickly estimated by a removal-based method. Additionally, we propose a topological entropy loss from the perspective of topology to avoid excessive information loss in the local structure during unlearning. Extensive experiments conducted on five real-world datasets demonstrate that INPO-based model achieves state-of-the-art performance on all forget quality metrics while maintaining the model's utility. Codes are available at \href{https://github.com/sh-qiangchen/INPO}{https://github.com/sh-qiangchen/INPO}.
