Romain Bourneuf

Who am I?

I am a Master 2 student at ENS de Lyon, currently doing a research internship under the supervision of Stéphan Thomassé in the team MC2 at LIP (ENS de Lyon).


My main interests lie in graph theory and combinatorics, especially in structural graph theory and extremal combinatorics.

Personal Info

  • Email: romain.bourneuf(at)
  • Office: Bureau des stagiaires, LIP - ENS de Lyon, 46 allée d'Italie, 69364 Lyon Cedex 07.
  • My CV: (PDF)

Academic background


2021 - 2023

Master's student at ENS de Lyon.

I mostly studied graph theory, combinatorics, algebra, cryptography and complexity.

2020 - 2021

Licence's degree at ENS de Lyon.

I studied fundamental computer science and mathematics.

2018 - 2020

Scientific Preparatory Class at Lycée Chateaubriand, Rennes.

Two years studying mathematics, computer science and physics in order to join the ENS.


Early 2023

6 months internship with Stéphan Thomassé at ENS de Lyon, France.

The aim of this internship was to study the χ-boundedness of graphs of bounded twin-width. I also studied other problems related to strctures of bounded twin-width. You can find here my master's thesis and the slides of my defense.

Summer 2022

4 months internship with Alon Rosen at Bocconi University, Milano, Italy.

During this internship, I studied the complexity of various total search problems related to extremal combinatorics.

Summer 2021

6 weeks internship with Marthe Bonamy at LaBRI, Bordeaux, France.

This internship was my first experience with graph theory. I studied Brandes' algorithm to compute the betweenness centrality in a graph.


French (native tongue)
English (fluent)
Spanish (intermediate)



Bounded twin-width graphs are polynomially χ-bounded. With Stéphan Thomassé.

A tamed family of triangle-free graphs with unbounded chromatic number . With Édouard Bonnet, Julien Duron, Colin Geniet, Stéphan Thomassé, Nicolas Trotignon.

Factoring Pattern-Free Permutations into Separable ones . With Édouard Bonnet, Colin Geniet, Stéphan Thomassé.


PPP-Completeness and Extremal Combinatorics. With Lukáš Folwarczný, Pavel Hubáček, Alon Rosen, Nikolaj Ignatieff Schwartzbach, ITCS 2023.


Conferences & Workshops


Innovations in Theoretical Computer Science, ITCS 2023, MIT. PPP-Completeness and Extremal Combinatorics. (Slides)

Workshops as a speaker

FPT Fest in the honour of Mike Fellows, Bergen, 2023. Bounded twin-width graphs are polynomially χ-bounded. (Slides)

1st Workshop on Twin-Width, Aussois, 2023. Bounded twin-width graphs are polynomially χ-bounded. (Slides)

Workshops as a non-speaker

Digraphs meeting, Sète, 2023.

Milan Theory Workshop, Bocconi, 2022.


Club de mathématiques discrètes