@article{when2thinklearningdifficultyawarelengthc,
  title = {When2Think: Learning Difficulty-Aware Length Control for Efficient Hybrid Reasoning Models},
  author = {Jaejun Shim and HyunJin Kim and Young Jin Kim and JinYeong Bak},
  year = {2026},
  eprint = {2609.19671},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2609.19671},
}