General Prerequisites:

Good command of Part A Integration, Probability and Differential Equations 1 are essential; the main concepts which will be used are the convergence theorems and the theorems of Fubini and Tonelli, and the notions of measurable functions, integrable functions, null sets and L^p spaces. The Cauchy-Lipschitz theory and Picard´s theorem proofs will be used. Basic knowledge of random variables, laws, expectations, and independence are needed. A good working knowledge of Part A Core Analysis (metric spaces) is expected. Knowledge of B8.1 Probability, Measure and Martingales will certainly help but it is not essential.

Course Term: Hilary
Course Weight: 1
Course Level: M
Course Overview:

This course will serve as an introduction to optimal transportation theory, its application in the analysis of PDE, and its connections to the macroscopic description of interacting particle systems.

Lecturer(s):

Prof. Jose Carrillo de la Plata

Assessment Type:

2-hour written examination paper

Learning Outcomes:

Getting familar with the Monge-Kantorovich problem and transport distances. Derivation of macroscopic models via the mean-field limit and their analysis based on contractivity of transport distances. Dynamic Interpretation and Geodesic convexity. A brief introduction to gradient flows and examples.

Course Synopsis:
  1. Interacting Particle Systems & PDE
  • Granular Flow Models and McKean-Vlasov Equations.
  • Nonlinear Diffusion and Aggregation-Diffusion Equations.
Optimal Transportation: The metric side
  • Functional Analysis tools: weak convergence of measures. Prokhorov’s Theorem. Direct Method of Calculus of Variations.
  • Monge Problem. Kantorovich Duality.
  • Transport distances between measures: properties. The real line. Probabilistic Interpretation: couplings.
Mean Field Limit & Couplings
  • Continuity Equation: measures sliding down a convex valley.
  • Dobrushin approach: derivation of the Aggregation Equation.
  • Boltzmann Equation for Maxwellian molecules: Tanaka Theorem.
An Introduction to Gradient Flows
  • Dynamic Interpretation of optimal tranport.
  • McCann’s Displacement Convexity: Internal, Interaction and Confinement Energies.
  • Gradient Flows: Differential and metric viewpoints.