PAC-Bayes Generalisation Bounds for Heavy-Tailed Losses through
Supermartingales
- URL: http://arxiv.org/abs/2210.00928v2
- Date: Mon, 24 Apr 2023 16:00:01 GMT
- Title: PAC-Bayes Generalisation Bounds for Heavy-Tailed Losses through
Supermartingales
- Authors: Maxime Haddouche and Benjamin Guedj
- Abstract summary: We contribute PAC-Bayes generalisation bounds for heavy-tailed losses.
Our key technical contribution is exploiting an extention of Markov's inequality for supermartingales.
Our proof technique unifies and extends different PAC-Bayesian frameworks.
- Score: 5.799808780731661
- License: http://creativecommons.org/licenses/by-nc-sa/4.0/
- Abstract: While PAC-Bayes is now an established learning framework for light-tailed
losses (\emph{e.g.}, subgaussian or subexponential), its extension to the case
of heavy-tailed losses remains largely uncharted and has attracted a growing
interest in recent years. We contribute PAC-Bayes generalisation bounds for
heavy-tailed losses under the sole assumption of bounded variance of the loss
function. Under that assumption, we extend previous results from
\citet{kuzborskij2019efron}. Our key technical contribution is exploiting an
extention of Markov's inequality for supermartingales. Our proof technique
unifies and extends different PAC-Bayesian frameworks by providing bounds for
unbounded martingales as well as bounds for batch and online learning with
heavy-tailed losses.
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