An introduction to evolution PDEs

Applied and Theoretical Mathematics - Master's Year 2

PSL University, September-December 2024



 

Chapters 0 - Prerequisite 
A prerequisite is also the basis of applied functional analysis as one can find (for instance) in the two following classical references:
H. Brézis, (French) [Functional analysis, Theory and applications], Masson, Paris, 1983: 
Chap 1, Chap 2, Chap 3, Chap 4, Chap 5, Chap 6, Chap 8, Chap 9
Lieb & Loss, Analysis, Graduate Studies in Mathematics, 14, American Mathematical Society, Providence, RI, 1997: 
Chap 1, Chap 2, Chap 5, Chap 6, Chap 7 (from 7.1 to 7.10),
Chap 8 (from 8.1 to 8.12), Chap 9
The color notation means that one must know absolutely, be familiarized with, have read at least once that matter.
 


A prerequisite for the analysis of evolution PDE (in order to establish pointwise estimates for both
existence theory and long time asymptotic analysis) is the so-called Gronwall lemma presented here
- On the Gronwall Lemma, essentially sections 1 & 2 (updated October 2020)


A tentative plan is the following :

Chapter  1 - Variational solution for parabolic equation, chapter 1 (updated October 2023)
Existence of solutions for parabolic equations by the mean of J.-L. Lions' variational approach.
 

Chapter  2 - De Giorgi-Nash-Moser theory and beyond for parabolic equations
We establish the ultracontractivity property of parabolic equations using different approaches developed by De Giorgi, Nash, Moser
and Boccardo-Gallouët. We deduce existence and uniqueness of solutions to parabolic equations in a Lp & M1 frameworks.
We next establish the Holder regularity and the Harnack inequality.


Chapter  3 -  Evolution equation, semigroup and longtime behaviour
Linear evolution equation and semigroup. Semigroup and generator.
Duhamel formula and mild solution. Coming back to the well-posedness issue. 
Doblin-Harris theorem of convergence and the Krein-Rutman theory.
 
 


See also the material of previous academic years and the last years exams:
Exam 2013-2014
Exam 2014-2015
Exam 2015-2016
Exam 2016-2017
Exam 2017-2018
Exam 2018-2019
Exam 2019-2020
Exam 2020-2021
Exam 2021-2022
Exam 2022-2023
Exam 2023-2024

A more extended version of the present lecture will be available here soon