Hierarchical Multi-Agent Reinforcement Learning with Control Barrier Functions for Safety-Critical Autonomous Systems. - H. M. Sabbir Ahmad; Ehsan Sabouni; Alexander Wasilkoff; Param Budhraja; Zijian Guo 002; Songyuan Zhang; Chuchu Fan; Christos G. Cassandras; Wenchao Li 001 (CoRR, 2025)