Particle JISD2021 19th School on Interactions Between Dynamical Systems
and Partial Differential Equations

The JISD 2021 will be postponed to 2023 due to the Covid pandemic situation (in 2022 the JISD 2020 edition will take place, which has been postponed as well). The new dates will soon be available.

POSTPONED TO 2023 - 19th School on Interactions Between Dynamical Systems and Partial Differential Equations (JISD2021)

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Advanced course / School
From June 19, 2023
to June 23, 2023


The School on Interactions between Dynamical Systems and Partial Differential Equations (JISD) is an international summer school that takes place at the School of Mathematics and Statistics of the Universitat Politècnica de Catalunya (UPC) since 2002. The last three editions have been held at the Centre de Recerca Matemàtica (CRM).
The JISD is an annual meeting between experts and young researchers in Dynamical Systems and Partial Differential Equations (PDEs). It is designed to encourage and enhance exchange of knowledge and methods, with the goal of advancing the study of cutting edge problems in the aforesaid fields of mathematics and with the aim of fostering the interaction among the participants. The symposium is aimed at local researchers, as well as scientists from the rest of Spain and foreign countries. It is organized into four advanced courses of about 7 hours and complemented by a poster session by young researchers. Throughout the latest editions the attendance numbers have ranged between 60 and 100 participants, mostly internationals.
A primary objective of the JISD is to attract talented young researchers who can present a poster to put them in condition to benefit from the exposure to world-leading experts, and help them establish working relationships that could prove critical for their short and long term success. An especially strong effort has been devoted in past years to encourage the participation of undergraduates, PhDs and postdocs from developing countries and, more generally, young researchers who may encounter difficulties in accessing an adequate financial support. 


Transfer operators and anisotropic spaces for Sinai billiards by Prof. Viviane Baladi (CNRS, France)
We will present an approach to the statistical properties of two-dimensional dispersive billiards (discrete and continuous-time) using transfer operators acting on anisotropic Banach spaces of distributions. We will survey results by Demers, Zhang, Liverani, etc, and joint work with Demers and Liverani on the SRB measure, as well as joint work with Demers on the measure of maximal entropy and more general equilibrium states.​
Dynamical spectral determination and rigidity by Prof. Jacopo de Simoi (University of Toronto, Canada)
The classical inverse problem asks to what extent it is possible to determine the shape of a domain D of the real plane (or of a surface), by the knowledge of all eigenvalues of the Laplace operator on D with assigned boundary conditions. A dynamical version of this question can be stated by replacing the set of eigenvalues of the Laplacian with the Length spectrum, that is the set of all lengths of all possible closed billiard orbits on D (or all closed geodesics in the case of manifolds). In these lectures, we will show the deep connection between the Laplace and the dynamical problem, we will present in detail some results on the dynamical side and explore the possible outcomes of the current research in this direction.
The regularity theory for Bernoulli type free boundary problems by Prof. Guido de Philippis (Courant Institute, US)
I will present an overview on the regularity theory for Bernoulli like free boundary problem, starting from the seminal work of Alt-Caffarelli in the 80’s to the recent developments obtained in collaboration with L. Spolaor and B. Velichkov.
The obstacle problem: regularity of the free boundary and analysis of singularities by Prof. Joaquim Serra (ETH Zürich, Switzerland)
The classical obstacle problem is a very paradigmatic free boundary problem with several applications in physics, probability, potential theory, finance, etc. It is equivalent, after certain transformations, to other well-known free boundary problems such as the Stefan problem.
The goal of the course will be to give an introduction to the regularity theory for the free boundary in the obstacle problem. On the first part of the course, we will revisit the classical theory from the 1970’s (although not always following the original proofs). We will start discussing the existence, uniqueness, and optimal regularity of the solutions. Later we will explain some insightful examples of Levy, Kinderleherer, and Niremberg of solutions with singular free boundaries, which are constructed using complex variables. After, we shall prove the existence of blow-ups and their classification leading to the celebrated dichotomy of Caffarelli. Finally, we will discuss how to prove smoothness of the free boundary near points which have blow-ups of regular type.
On the second part of the course, we will introduce some recent developments of the theory regarding the structure of the singular set. We will introduce monotonicity formulae methods and explain why the fine analysis of singularities of the obstacle problem leads to the analysis of singular points for the so called Signorini problem.
Finally, we will prove, in the 2D case, some new results (with A. Figalli) on higher order expansions at singular points. If time allows, we will explain roughly how the content of the course is fundamental in the recent proof in dimensions 3 and 4 of a conjecture of Schaeffer on the generic regularity of the free boundary (in a joint work with A. Figalli and X. Ros-Oton).

Organizing Committee

Xavier Cabré​ ICREA and ​Universitat Politècnica de Catalunya
Gyula Csato Universitat de Barcelona
Amadeu Delshams​ ​Universitat Politècnica de Catalunya
​Filippo Giuliani ​​​Universitat Politècnica de Catalunya​
​Marcel Guàrdia​ ​​Universitat Politècnica de Catalunya
Tere M. Seara​ ​Universitat Politècnica de Catalunya

Scientific Committee

Scott Amstrong Université Paris – Dauphine​
Jean Pierre Eckmann ​ ​Université de Genève
​Jean-Michel Roquejoffre ​Paul Sabatier University
​Susanna Terracini ​Università de Torino

Poster session

If you wish to present a poster, please submit the following form before – dates TBP.

Resolutions will be sent before – dates TBP.


In order to increase the number of young researchers participating in this activity, the CRM announces a call for those participants interested in taking part in this activity. This grant includes a reduced registration fee and housing in a shared apartment on campus.

Application deadline for grants: dates TBP (Resolutions will be sent before dates TBP)

The EMS offers some travel grants to young mathematicians from less-favoured regions within the geographical area of EMS membership for presenting results at conferences or attending courses, or for research stays in foreign countries, normally up to a maximum of 900 euros in each case or 500 euros for trips within Europe.
Eligible researchers should use this online form​ in order to apply for travel grants.

Lodging information

  • For lodging in the area please click here​
  • For off-campus and family accommodation click here​​​

Organized by



For inquiries about the program please contact the research programme’s coordinator Ms. Núria Hernández at​​