Hao Liu Zhengren Wang Xi Chen Zhiyu Li Feiyu Xiong Qinhan Yu Wentao Zhang HopRAG: Multi-Hop Reasoning for Logic-Aware Retrieval-Augmented Generation. 2025 February abs/2502.12442 CoRR https://doi.org/10.48550/arXiv.2502.12442 db/journals/corr/corr2502.html#abs-2502-12442 streams/journals/corr