@article{proximalpolicyoptimizationwithadaptive,
  title = {Proximal Policy Optimization with Adaptive Threshold for Symmetric Relative Density Ratio},
  author = {Taisuke Kobayashi},
  year = {2022},
  eprint = {2203.09809},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2203.09809v1},
}