BARREL: Boundary-Aware Reasoning for Factual and Reliable LRMs - Yang, Junxiao; Tu, Jinzhe; Liu, Haoran; Wang, Xiaoce; Zheng, Chujie; Zhang, Zhexin; Cui, Shiyao; Chen, Caishun; He, Tiantian; Wang, Hongning; Ong, Yew-Soon; Huang, Minlie (International Conference on Learning Representations, 2026)