Machine learning models may inadvertently memorize sensitive, unauthorized, or malicious data, posing risks of privacy violations, security breaches, and performance deterioration. To address these issues, machine unlearning has emerged as a critical technique to selectively remove specific training data points' influence on trained models. This paper provides a comprehensive taxonomy and analysis of machine unlearning research. We categorize existing research into exact unlearning that algorithmically removes data influence entirely and approximate unlearning that efficiently minimizes influence through limited parameter updates. By reviewing the state-of-the-art solutions, we critically discuss their advantages and limitations. Furthermore, we propose future directions to advance machine unlearning and establish it as an essential capability for trustworthy and adaptive machine learning. This paper provides researchers with a roadmap of open problems, encouraging impactful contributions to address real-world needs for selective data removal.

机器遗忘是一项关键技术，用于选择性地移除训练数据点对训练模型的影响。本文提供了机器遗忘研究的全面分类和分析，并回顾了最新的解决方案，讨论了其优势和限制，并提出了未来的发展方向，以推动机器遗忘作为一项必要的可信和自适应机器学习能力。

机器取消学习：解决方案与挑战