Hédi Hadiji

I am a post-doc in the team of Tim van Erven at the Korteweg-de Vries Institute for Mathematics, of the University of Amsterdam, where I work on adaptive online learning.

I defended my PhD in 2020 at the LMO of the Université Paris-Saclay, studying multi-armed bandits with a focus on adaptation problems, under the supervision of Gilles Stoltz and Pascal Massart. Before that, I graduated from the École Polytechnique in 2016. I completed the Part III of the Mathematical Tripos at the University of Cambridge (2015-2016) and also obtained a Master's degree (M2) in Probability and Statistics at Orsay in 2016-2017.

Contact me at: h dot hadiji at uva dot nl (or at) hedi dot hadiji at gmail dot com



Distributed Online Learning for Joint Regret with Communication Constraints, with Dirk van der Hoeven and Tim van Erven, 2021 submitted [Arxiv]

Diversity-preserving K-armed bandits, revisited, with Sébastien Gerchinovitz, Jean-Michel Loubes, and Gilles Stoltz, 2020, submitted [HAL]

Adaptation to the Range in K-Armed Bandits, with Gilles Stoltz, 2020, submitted [HAL]

Polynomial cost of adaptation for X-armed bandits, Advances in Neural Information Processing Systems (NeurIPS), 2019 [arxiv, poster]

KL-UCB-switch: optimal regret bounds for stochastic bandits from both a distribution-dependent and a distribution-free viewpoints, with Aurélien Garivier, Pierre Ménard and Gilles Stoltz, 2018, submitted [arxiv]


Polynomial cost of adaptation for X-armed bandits, 12 February 2020, Thematic Statistics Seminar in Machine Learning, Leiden University

Polynomial cost of adaptation for X-armed bandits, 17 October 2019, Seminar of the Institut für Mathematische Stochastik (IMST), Otto-von-Guericke-Universität, Magdeburg.

Polynomial cost of adaptation for X-armed bandits, 24 September 2019, Workshop of the Celeste INRIA team

X-armed bandits, June 2019, Séminaire des doctorants, Orsay

KL-UCB-switch, May 2018, 50èmes Journées de Statistique, EDF Lab Paris Saclay


My PhD thesis, and the slides from my defense.

Reviewing services: COLT 2021, UAI 2021, Neurips 2019 (top 400 reviewer), Mathematics of Operations Research, SIMODS.

I enjoy implementing the algorithms I design: my personal python bandit laboratory for numerical experiments.


I am currently TAing for the Machine Learning Theory class of the MasterMath program.

For the year 2019-2020, I was a teaching assistant for the following classes at Orsay:

  • Mathematical Statistics (M1, 1st year Master's students) [webpage]
  • Statistics for Biologists, including R lab sessions (L2, 2nd year students)

During the years 2017-2019, at the IUT de Sceaux. I TA'ed the courses:

  • Mathematics for Business, Mathematics and Personal Finance 1st year students
  • Elementary Statistics, 2nd year students


I enjoy bouldering and free climbing, and I'd like to be better at chess. I read a lot of comics/graphic novels, and sometimes real books. When I feel free, I like to go to the movies.

My first name is Hédi and my last name is Hadiji. In Arabic my first name is written هادي. In English (or in French, actually) pronounce my name like "Eddy".