Romain Bourneuf

Who am I?

I am a Master 2 student at ENS de Lyon, currently doing a research internship under the supervision of Marcin Pilipczuk at University of Warsaw, Poland.


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


February 2024 - July 2024

5 months internship with Marcin Pilipczuk at University of Warsaw, Poland.

I am studying various structural and algorithmic properties of hereditary graph classes.

September 2023 - February 2024

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

I studied the algorithmic aspects of decomposing a graph into 4-connected components.

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 degree at ENS de Lyon.

I studied various topics, including 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.



On polynomial degree-boundedness. With Matija Bucić, Linda Cook, James Davies. (See on Arxiv)

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

Bounded twin-width graphs are polynomially χ-bounded. With Stéphan Thomassé. (See on Arxiv)


Factoring Pattern-Free Permutations into Separable ones. With Édouard Bonnet, Colin Geniet, Stéphan Thomassé, SODA 2024. (See on Arxiv)

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


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

EPIT - Graphs and Algorithms: Conjectures, Aussois, 2024.

Sparse Graphs Coalition 2024 Session 1, Online, 2024.

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