Qiang Zhang 0051 Boli Chen Fanrui Zhang Ruixue Ding Shihang Wang Qiuchen Wang Yinfeng Huang Haonan Zhang Rongxiang Zhu Pengyong Wang Ailin Ren Xin Li 0144 Pengjun Xie Jiawei Liu 0001 Ning Guo Jingren Zhou 0001 Zheng-Jun Zha ArenaRL: Scaling RL for Open-Ended Agents via Tournament-based Relative Ranking. 2026 January abs/2601.06487 CoRR https://doi.org/10.48550/arXiv.2601.06487 db/journals/corr/corr2601.html#abs-2601-06487 streams/journals/corr