S4B1 - Graduate Seminar in Analysis - KAM and Nash-Moser

Winter term 2024/25

Dr. Jan Bohr
Prof. Dr. Herbert Koch

Organisational details

Overview

The inverse function theorem for Banach spaces is ubiquitous in nonlinear analysis and differential geometry. Its usage is however limited to situations where there is no loss of derivatives, that is, where one may choose function spaces of a fixed regularity in which the linearised problem can be solved. The Nash-Moser theorem is an inverse function theorem that can deal with a loss of derivatives and is commonly formulated on spaces of smooth functions (or more generally on Frechet spaces). In the seminar we will discuss and prove a version of the Nash-Moser theorem and explore some situations where its usage is/is not warranted. We'll also explore an application of the ideas behind the Nash-Moser theorem to Hamiltonian mechanics and discuss a version of the celebrated KAM (Kolmogorov-Arnold-Moser) theorem.

See here for more information, including a list of talks and literature recommendations.

Prerequisites: Basics of linear PDE and functional analysis

Schedule of talks

October 23- Jan Bohr Hamiltonian mechanics: integrable systems and action-/angle variables

October 30- Rongxuan Deng The classical KAM theorem: statement and reductions

November 6- Abelard Malvin The classical KAM theorem: overview of proof

November 13- Shao Liu The classical KAM theorem: the KAM step

November 20- Herbert Koch Approximations by trigonometric polynomials

November 27- Shao Liu The classical KAM theorem: Iteration of the KAM steps

December 4- Dies Academicus

December 11- Matteo Licheri Gunther's proof of the Isometric Embedding theorem

December 18- Jan Bohr The Nash-Moser Inverse Function theorem

December 25- Christmas break

January 1- Christmas break

January 8- Talk 11 TBA

January 15- Talk 12 TBA

January 22- Talk 13 TBA