@article{difficultybasedpreferencedataselectionby,
  title = {Difficulty-Based Preference Data Selection by DPO Implicit Reward Gap},
  author = {Xuan Qi and Rongwu Xu and Zhijing Jin},
  year = {2025},
  eprint = {2508.04149},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2508.04149},
}