FedWMSAM: Fast and Flat Federated Learning via Weighted Momentum and Sharpness-Aware Minimization - Li, Tianle; Huang, Yongzhi; Jiang, Linshan; Liu, Chang; Xie, Qipeng; Du, Wenfeng; Wang, Lu; Wu, Kaishun (Advances in Neural Information Processing Systems, 2025)