@article{optunaconstrainedtreestructuredparzenest,
  title = {Optuna Constrained Tree-Structured Parzen Estimator Is a Joint Density Generalization of c-TPE},
  author = {Shuhei Watanabe and Kaichi Irie},
  year = {2026},
  eprint = {2606.09889},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2606.09889},
}