@inproceedings{guo-etal-2026-hidifftir,
    title = "{H}i{D}iff{TIR}: Hierarchical Difficulty-Aware Policy Optimization for Multi-Turn Tool-Integrated Reasoning",
    author = "Guo, Yucan  and
      Wang, Xiaohan  and
      Su, Miao  and
      Guan, Saiping  and
      Hou, Zhongni  and
      Chai, Jiajun  and
      Lin, Wei  and
      Yin, Guojun  and
      Jin, Xiaolong  and
      Guo, Jiafeng  and
      Cheng, Xueqi",
    editor = "Lee, Hung-Yi  and
      Dev, Sunipa  and
      Li, Jessy  and
      Elliott, Desmond",
    booktitle = "Findings of the {A}ssociation for {C}omputational {L}inguistics: {EMNLP} 2026",
    month = oct,
    year = "2026",
    address = "Budapest, Hungary",
    publisher = "Association for Computational Linguistics",
    url = "https://aclanthology.org/2026.findings-emnlp.299/",
    pages = "6325--6342",
    ISBN = "979-8-89176-462-0"
}