@article{optimalnonasymptoticlowerboundonthe,
  title = {Optimal Non-Asymptotic Lower Bound on the Minimax Regret of Learning with Expert Advice},
  author = {Francesco Orabona and David Pal},
  year = {2015},
  eprint = {1511.02176},
  archivePrefix = {arXiv},
  url = {http://arxiv.org/abs/1511.02176v1},
}