Romain Bourneuf

Who am I?

I am a Master 2 student at ENS de Lyon, currently doing a research internship under the supervision of Johannes Carmesin at University of Birmingham, UK.


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

Personal Info

  • Email: romain.bourneuf(at)
  • My CV: (PDF)

Academic background


September 2023 - February 2024

5 months internship with Johannes Carmesin at University of Birmingham, UK.

I am studying a variety of topics during this internship, mostly related to graph connectivity.

February 2023 - July 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 structures 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.


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.


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



On polynomial degree-boundedness. With Matija Bucić, Linda Cook, James Davies.

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

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


Factoring Pattern-Free Permutations into Separable ones. With Édouard Bonnet, Colin Geniet, Stéphan Thomassé, SODA 2024.

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


Conferences & Events


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

Events as a speaker

3rd Workshop on Complexity and Algorithms, CoA 2023, Paris. PPP-Completeness and Extremal Combinatorics. (Slides)

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)

Events as a non-speaker

Structural Graph Theory Workshop, Bȩdlewo, 2023.

Structural Graph Theory Bootcamp, Warsaw, 2023.

Digraphs meeting, Sète, 2023.

Milan Theory Workshop, Bocconi, 2022.


Club de mathématiques discrètes