RLVER: Reinforcement Learning with Verifiable Emotion Rewards for Empathetic Agents - Wang, Peisong; Ma, Ruotian; Zhang, Bang; Chen, Xingyu; He, Zhiwei; Luo, Kang; Lv, Qingsong; Jiang, Qingxuan; Xie, Zheng; Wang, Shanyi; LI, CIXING; Li, Yuan; et al. (International Conference on Learning Representations, 2026)