CCS Concepts:
  $\bullet$ Computing methodologies $\rightarrow$ Machine learning; Artificial intelligence; 
  $\bullet$ Security and privacy; 
  • Theory of computation;
1 INTRODUCTION
2 THE SLR METHOD OF THE SURVEY
3 BACKGROUND
4 CENTRALIZED MACHINE UNLEARNING
5 FEDERATED UNLEARNING
6 UNLEARNING EVALUATION AND VERIFICATION
7 PRIVACY AND SECURITY THREATS ON MACHINE UNLEARNING
8 MACHINE UNLEARNING APPLICATIONS
9 LESSONS LEARNED AND DISCUSSIONS
10 SUMMARY