 Pierre Aboulker

Département Informatique de l'ENS,
45 Rue d'Ulm,
75005 Paris  FRANCE.Tel: A remplir
Courriel: pierreaboulker@gmail.com
Short bio
Since 2018 I am an Assistant Professor in the Talgo (Theory, ALgorithms, Graphs, and Optimization) team at the Computer Science Department of École normale supérieure, Paris, France.Since 2019 I am in the board of the section 6 of the National Committee for Scientific Research For more information, click here.
Before: I have done my PhD with Nicolas Trotignon between 2010 and 2013. I have been a postdoc a Concordia University in Montréal with Vašek Chvátal, in Santiago de Chile at Andres Bello university with José Aliste, in SophiaAntipolis under the direction of Frédéric Havet, in Université Libre de Bruxelles under the direction of Samuel Fiorini and a I was an ATER in Université GrenobleAlpes.
Research interests
I am interested in graph theory (nonoriented and oriented), in some problems related to geometry in metric spaces and betweenness. I have also done incursions in combinatorial optimization and distributed algorithms.In graph theory I am particularly interested in substructures that must apear in a graph or a digraph with particular property. Typical examples: if a graph has large chromatic number, what can you say about its induced subgraphs? Or if a digraph has large minimum outdegree, what can we say about its subgraphs? In geometry, I mainly work on the ChenChvátal Conjecture, that proposes a vast generalisation of the geometric de BruijnErdös Theorem.
Published papers
Graphs that do not contain a cycle with a node that has at least two neighbors on it
with M. Radovanovic, N. Trotignon, K. Vuskovic, in SIAM Journal on Discrete Mathematics, 2012.
Linear balanceable and subcubic balanceable graphs
with M. Radovanovic, N. Trotignon, T. Trunck, K. Vuskovic, in Journal of Graph Theory, 2013.
Excluding 4wheels,
inJournal of Graph Theory, 2014.
Number of lines in hypergraphs
with A. Bondy, X. Chen, E. Chiniforooshan, V. Chvátal, P. Miao, in Journal of Graph Theory, 2014.
Excluding cycles with a fixed number of chords
with N. Bousquet, Discrete Applied Mathematics, 2015.
ChenChvàtal conjecture for distance hereditary graphs
with R. Kapadia, European Journal of Combinatorics, 2015.
Vertex elimination orderings for hereditary graph classes
with P. Charbit, N. Trotignon, K. Vušković), in Discrete Mathematics, 2015.
Wheelfree planar graphs
with M. Chudnovsky, P. Seymour and N. Trotignon, in European Journal of Combinatorics, 2015.
Excluding clock
with Z. Li, S. Thomassé, Electronic Notes in Discrete Mathematics, 2015.
Lines, metric spaces and betweenness
with X. Chen, G. Huzhang, R. Kapadia, C. Supko, in Discrete & Computational Geometry, 2016.
A new class of graphs that satisfies the ChenChv\'atal Conjecture
with M. Matamala, P. Rochet and J. Zamora, in Journal of Graph Theory, 2016.
De BruijnErdos type theorems for graphs and posets
with G. Lagarde, D. Malec, A. Methuku, C. Tompkins in Discrete Mathematics, 2017.
Colouring graphs with constraints on connectivity
with N. Bretell, F. Havet, N. Trotignon, in Journal of Graph Theore, 2017.
Chibounded families of oriented graphs
with J. BangJensen, N. Bousquet, P. Charbit, F. Havet, F. Maffray, J. Zamora, in
Journal of Graph Theory, 2018.
A tight Erd\H{o}sP\'osa function for wheel minors (with S. Fiorini, T. Huynh, G. Joret, J.F. Raymond et I. Sau), SIAM Journal on Discrete Mathematics, 2018.
Distributed coloring in sparse graphs with fewer colors
with M. Bonamy, N. Bousquet, L. Esperet, in PODC 2018 and in Electronic Journal of Combinatorics 2019.
Subdivisions in digraphs of large outdegree or large dichromatic number
with N. Cohen, W. Lochet, F. Havet, P. Mourra, S. Thomassé, in Electronic Journal of Combinatorics, 2019.
Extension complexity of the correlation polytop
with S. Fiorini, T.~Huynh, M.~Macchia, J.~Seif, in Operations Research Letters, 2019.
Grundy Coloring & friends, HalfGraphs, Bicliques
with E. Bonnet, EJ Kim, F. Sikora, STACS 2020.
Submited papers
On the treewidth of evenholefree graphs
with I. Adler, EJ Kim, N.L.D. Sintiari and N. Trotignon.
Graphs with no induced house nor induced hole have the de BruijnErd\H {o} s property
with L. Beaudou, M. Matamala, J. Zamora.
Extension of GyarfasSumner conjecture to digraphs
with P. Charbit, R. Naserasr.
On the dichromatic number of surfaces.
with Frédéric Havet, Kolja Knauer, Clément Rambaud.
Decomposing and colouring some locally semicomplete digraphs.
with Guillaume Aubian, Pierre Charbit.
Manucripts
On wheelfree graphs, (P. Aboulker, F. Havet, N. Trotignon),
Encadrements
Doctorat:
20202023, Guillaume Aubian: Coloring Digraphs.
Stages de M2:
2020 (5 months), Guillaume Aubian (ENS Cachan): Extending Brook's theorem to digraphs.
2021 (5 months), Sarah Houdaigoui (ENS Cachan): Optimization problems in even hole free graphs.
Stages de L3:
2019, Nina Heloïn (ENS Ulm): around the de BruijnErdos Theorem
2020, Nicolas Daire (ENS Ulm): contraction de graphes
2020, Clément Rambaut (ENS Ulm): dicoloring of graph embedded on surfaces.
2021, Juliette Schabanel (ENS Ulm): dicochromatic number of planar graphs.
2021, Hectore Buffière (ENS Ulm): forced structure in digraphs with large dichromatic number.
2021 (5 months), Gaia Carenini (University School for Advanced Studies, Italia): Chen Chvatal Conjecture.
Enseignement
Initiation à la programmation pour noninformaticiens en Python
Graph Minor Theory and its algorithmic consequences. Supports:
 Graph Theory by Diestel This is a textbook on graph theory, chapter 12 can be used as companion notes for this class.
 Graph Minor Theory by Lovasz A short overview of graph minor theory. It is a particularly enlightening lecture, I strongly advice you to read it
 Slides of the course
 Notes and exercises for course 1
 List of subjects for presentation (you can also choose your on subject):
 Combinatorial Topology of Surfaces This article gives a classification of all surfaces. Graph embedding on surfaces play a crucial role in graph minor theory.
 Survey on Perfect Graphs This is a very nice survey on perfect graphs, it contains more then enough material for a beautiful presentation.
Mobilité
2019: 1 week in Leeds visiting Isolde Adler.
2019: 3 weeks in Daejong (South Korea) at the Institute for Basic science.
2019: 3 weeks in Santiago de Chile, at Universidad de Chile, visiting Martin Matamala and jose Zamora.
Some recent talks
Subdivisions in oriented graphs, JGA 2016, November 2016.
Subdivisions in oriented graphs, SIWAG, september 2016.
Configurations in oriented graphs, Workshop STINT, january 2016.
Lines induced by betweenness relations, Conference: Connection in Discrete mathematics, in Simon Fraiser University (Vancouver, Canada), June 2015
Excluding clocks, VIII LatinAmerican Algorithms, Graphs and Optimization Symposium, in Fortaleza, Brasil, Mai 2015.
Avancées sur la conjecture de ChenChvátal, JGA, Dijon, november 2014.
Lines, betweenness and metric spaces, STRUCO, Prague, octber 2014.
Avancées sur la conjecture de ChenChvátal, séminaire Algorithmique distribuée et Graphes, Paris VII, october 2014.
A generalisation of a de Bruijn Erdos Theorem, SIAM Conference on Discrete Math, Minneapolis, United states, june 2014
Graphs with no 4wheels, séminaire Optimisation Combinatoire du GSCOP (Grenoble), Avril 2012.
Around wheelfree graphs, séminaire Graphes et Structures Discrètes, ENS Lyon, Février 2012.
Autour des graphes sans roues, séminaire de Combinatoire Algébrique et Géométrique ( Paris 6), Décembre 2011.
Les graphes sans roues, JGA, Lyon, Novembre 2011.