@article{JMLR:v27:22-0358,
  author  = {Masahiro Kato and Kaito Ariu},
  title   = {The Role of Contextual Information in Best Arm Identification},
  journal = {Journal of Machine Learning Research},
  year    = {2026},
  volume  = {27},
  number  = {51},
  pages   = {1--61},
  url     = {http://jmlr.org/papers/v27/22-0358.html}
}