Léo Girardin

Photo de L. Girardin Contact details
Postal address:
Léo Girardin
Laboratoire de Mathématiques d’Orsay
Université Paris Sud, CNRS
Université Paris-Saclay
91405 Orsay Cedex
France
Office: 2G1
E-mail address: myfirstname.mylastname@math.u-psud.fr
The beautiful Iguazu Falls and some dude right in front of them.

Curriculum vitae

Here is an English version, there is a French version.

To be brief, my current position is postdoctoral fellow at Université Paris-Sud, funded by the Fondation Mathématique Jacques Hadamard and mentored by Danielle Hilhorst.

Research interests

My mathematical self currently leans toward reaction–diffusion partial differential equations and systems and mathematical models for population biology problems. 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, populations structured both in space and age, CRISPR-Cas9 gene drive reversal.

Responsibilities

I am 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

Publications

  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. Non-cooperative Fisher--KPP systems: traveling waves and long-time behavior. Nonlinearity, 2018, 31, 108-164.
  4. 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.)
  5. 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.
  6. Non-cooperative Fisher--KPP systems: asymptotic behavior of traveling waves. Mathematical Models and Methods in Applied Sciences, 2018, 28(06), 1067-1104 .
  7. with A. Zilio: Competition in periodic media: III -- Existence & stability of segregated periodic coexistence states. Journal of Dynamics and Differential Equations, 2019.
  8. 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.
  9. Two components is too simple: an example of oscillatory Fisher--KPP system with three components. Proceedings of the Royal Society of Edinburgh - A, 2019.
  10. 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.
  11. The effect of random dispersal on competitive exclusion -- A review. Accepted for publication in Mathematical Biosciences.

Research presentations

Posters

Slides

The slides of any talk I gave in the past are available on demand (simply email me). I am not uploading them on the web (anymore) because 1) it would consume too much disk space on the long term and 2) the n+1-th talk being most of the time an upgrade of the n-th talk, it seems pointless to provide the slides of both.

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”).

Pedagogical material (in French): in order to help the students, I revised the preexisting list of exercises and added indications for the students having difficulties:

Miscellaneous might-be-interesting stuff

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

My Publons profile.

I am among the Nonlinearity Outstanding Reviewers of 2018.

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).

I am a PhD Comics reader.

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).

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