English

Fano's inequality for random variables

Statistics Theory 2019-06-12 v3 Information Theory math.IT Statistics Theory

Abstract

We extend Fano's inequality, which controls the average probability of events in terms of the average of some ff--divergences, to work with arbitrary events (not necessarily forming a partition) and even with arbitrary [0,1][0,1]--valued random variables, possibly in continuously infinite number. We provide two applications of these extensions, in which the consideration of random variables is particularly handy: we offer new and elegant proofs for existing lower bounds, on Bayesian posterior concentration (minimax or distribution-dependent) rates and on the regret in non-stochastic sequential learning.

Keywords

Cite

@article{arxiv.1702.05985,
  title  = {Fano's inequality for random variables},
  author = {Sebastien Gerchinovitz and Pierre Ménard and Gilles Stoltz},
  journal= {arXiv preprint arXiv:1702.05985},
  year   = {2019}
}
R2 v1 2026-06-22T18:23:00.085Z