Léo Girardin

	Contact details
	Postal address: Léo Girardin Institut Camille Jordan Université Claude Bernard Lyon-1 43 boulevard du 11 novembre 1918 69622 Villeurbanne Cedex France
	Office: 113
	E-mail address: myfirstname.mylastname@math.cnrs.fr
© Chancellerie de Paris/Julien Benhamou

Curriculum vitae

I am a junior CNRS researcher affiliated with the team MMCS (Mathematical Modelling and Scientific Computing) at Institut Camille Jordan (UMR 5208) at Université Claude Bernard Lyon-1.

Full CV (PDF format): English version/French version.

Research interests

My mathematical self currently leans toward reaction–diffusion partial differential equations and systems and mathematical models for population biology (ecology, evolution, epidemiology, population genetics). In particular, I am interested in long-time qualitative behaviors: persistence, extinction and especially propagation phenomena (asymptotic spreading, traveling wave solutions and generalizations of these notions).

Secondary focuses worth mentioning are principal eigenvalues of parabolic and elliptic operators, non-local parabolic and elliptic PDEs, free boundary problems, singular limits and mathematical models for social sciences.

On the biological side, I have studied models of competitive displacement, territorial expansion, evolution of dispersal and spatial sorting in expanding ranges, evolution of Allee effect, populations structured both in space and age, CRISPR-Cas9 gene drive.

Responsibilities

I was the lead organizer of an interdisciplinary PDE–biology workshop in Orsay (France) on November 25th and 26th, 2019, thanks to a funding of the Fondation Mathématique Jacques Hadamard.

I was co-organizer of the SIMBAD biomathematics seminar and lead organizer of its first meeting (May 24th, 2016, LJLL, Paris).

PhD thesis

My PhD thesis was entitled Propagation phenomena and reaction–diffusion systems for population dynamics in homogeneous or periodic media and supervised by Grégoire Nadin and Vincent Calvez. You can find the manuscript here.

Research articles (with arXiv links)

Preprints

1. with M. Alfaro, F. Hamel and L. Roques: When the Allee threshold is an evolutionary trait: persistence vs. extinction. 2020.
2. with D. Hilhorst: Spatial segregation limit of traveling wave solutions for a fully nonlinear strongly coupled competitive system. 2020.
3. with F. Débarre: Demographic feedbacks can hamper the spatial spread of a gene drive. 2021.

Publications

On two-species competition--diffusion Lotka-Volterra systems

1. with G. Nadin: Travelling waves for diffusive and strongly competitive systems: relative motility and invasion speed. European Journal of Applied Mathematics, 2015, 26(04), 521-534.
2. Competition in periodic media: I -- Existence of pulsating fronts. Discrete and Continuous Dynamical Systems - Series B, 2017, 22(04), 1341-1360.
3. with G. Nadin: Competition in periodic media: II -- Segregative limit of pulsating fronts and "Unity is not Strength"-type result. Journal of Differential Equations, 2018, 265(01), 98-156.
4. with A. Lam: Invasion of open space by two competitors: spreading properties of monostable two-species competition--diffusion systems. Proceedings of the London Mathematical Society, 2019, 119(05), 1279-1335.
5. The effect of random dispersal on competitive exclusion -- A review. Mathematical Biosciences, 2019, 318, 108271.
6. with A. Zilio: Competition in periodic media: III -- Existence & stability of segregated periodic coexistence states. Journal of Dynamics and Differential Equations, 2020, 32, 257-279.

On non-cooperative Fisher--KPP systems

1. Non-cooperative Fisher--KPP systems: traveling waves and long-time behavior. Nonlinearity, 2018, 31, 108-164.
2. Addendum to 'Non-cooperative Fisher–KPP systems: traveling waves and long-time behavior'. Nonlinearity, 2018, 32, 168-171. (Contains the proof of extinction in the critical case.)
3. Non-cooperative Fisher--KPP systems: asymptotic behavior of traveling waves. Mathematical Models and Methods in Applied Sciences, 2018, 28(06), 1067-1104 .
4. Two components is too simple: an example of oscillatory Fisher--KPP system with three components. Proceedings of the Royal Society of Edinburgh - A, 2019.
5. with Q. Griette: A Liouville-type result for non-cooperative Fisher--KPP systems and nonlocal equations in cylinders. Acta Applicandae Mathematicae, 2020.

On gene drive reaction--diffusion models

1. with V. Calvez and F. Débarre: Catch me if you can: a spatial model for a brake-driven gene drive reversal. Bulletin of Mathematical Biology, 2019, 81(12), 5054-5088.

Research presentations

Posters

• Competition in periodic media: pulsating fronts & segregation. Presented at the poster session of the Séminaires de Mathématiques Supérieures 2016 (“Honorable Mention” award) (University of Alberta) and at the poster session of the summer school PDE and Probabilities for Life Sciences 2016 (CIRM).

Slides

The slides of any talk I gave in the past are available on demand (simply email me).

Teachings

2015–2018

During my PhD, I was tutoring (“Chargé de Mission d’Enseignement” in French) at UPMC, assigned to multivariable calculus courses (“UE 2M216” and “UE 2M256”).

Miscellaneous might-be-interesting stuff

An interview of me (in French) by the CNRS.

My ORCID profile (0000-0001-8201-2053).

My Publons profile.

I am among the Nonlinearity Outstanding Reviewers of 2018 and I am an IOP Publishing Trusted Reviewer.

I have a master degree in epistemology. The science studies, in its most general sense, still interest me strongly. I am inclined to discuss with anyone and to learn more about, for instance, the sociology of mathematics (a reference (in French)) or the history of population dynamics (a reference).

A fancier website will replace this austere page. Someday. (At least, web accessibility is not an issue here.)

During my free time, I practice and teach aikibudo (black belt 3rd dan).