Thematic Research Programme

Variational and geometrical methods in partial differential equations

Visits of scientific guests

Series of lectures given by Prof. Jacek Jendrej

About the lecturer

Jacek Jendrej, CNRS and Sorbonne Paris Nord University.
His research focuses on the long-term behavior of solutions to nonlinear wave equations, particularly on the study of multi-solitons. His work with A. Lawrie on the wave maps equation earned him the 'Cours de la Fondation Claude-Antoine Peccot' at the Collège de France in 2019, as well as the 'Juliusz Schauder Prize for Young Mathematicians' from Nicolaus Copernicus University in Toruń. He is a recipient of an ERC Starting Grant for his research in the field of nonlinear dispersive equations.

Course title: Dispersive partial differential equations

The aim of the course is to provide a brief introduction to the field of nonlinear dispersive equations.

  • 06.03.2024, 12:15 - 14:00, room no. 3250
    Lecture 1 - Oscillatory integrals and stationary phase
    In the first lecture, the notion of the Fourier Transform will be recalled and we will see a useful method from Harmonic Analysis called the "stationary phase approximation".
  • 08.03.2024, 10:15 - 12:00, room no. 5840
    Lecture 2 - Linear wave equations and Strichartz estimates
    The second lecture will be devoted to the linear wave equation and the Strichartz estimates, which provide a way of quantifying how waves spread in space as time passes.
  • 12.03.2024, 10:15 - 12:00, room no. 3260
    Lecture 3 - Equivariant wave maps equation and its well-posedness in the energy space
    In the final lecture, we will consider a particular nonlinear wave equation called the "equivariant wave maps equation". We will see that, thanks to the Strichartz estimates introduced in the previous lecture, well-posedness results for finite-energy initial data can be obtained as an easy application of the Banach fixed-point theorem.
Prerequisites: Functional Analysis, Partial Differential Equations

The aim of the lecture series is to present the proof of A. Lawrie and myself of the soliton resolution for equivariant wave maps.

  • 03.04.2024, 12:15 - 14:00, room no. 3250
    Lecture 4 - Overall strategy. Decay of energy in the self-similar region.
  • 05.04.2024, 10:15 - 12:00, room no. 5840
    Lecture 5 - Linear and nonlinear profile decomposition. Small kinetic energy implies bubbling.
  • 09.04.2024, 10:15 - 12:00, room no. 4060
    Lecture 6 - Modulation method.
  • 12.04.2024, 10:15 - 12:00, room no. 5840
    Lecture 7 - Conclusion of the proof.
Prerequisites: It will be helpful to know the contents of lectures 1, 2 and 3.