Codes and Expansions (CodEx) Seminar


Nick Trefethen (Harvard University)
Analytic Continuation and the One-Wavelength Principle

Analytic continuation is impossible or at least highly ill-conditioned in theory, depending how you frame the problem, yet sometimes surprisingly tractable in practice with the help of rational approximations computed by the AAA algorithm. The outline of the talk will be as follows:

  • Theorems (pretty gloomy)
  • Digression: blending functions and “fat branch cuts”
  • Experiments (pretty encouraging)
  • The one-wavelength principle