GraphRAG-R1: Graph Retrieval-Augmented Generation with Process-Constrained Reinforcement Learning. - Chuanyue Yu; Kuo Zhao; Yuhan Li; Heng Chang; Mingjian Feng; Xiangzhe Jiang; Yufei Sun; Jia Li; Yuzhi Zhang; Jianxin Li; Ziwei Zhang (CoRR, 2025)