Quasi-periodic solutions to nonlinear PDE

Quasi-periodic solutions to nonlinear PDE

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Wei-Min Wang , Université Paris-Sud
Jadwin Hall 111

We discuss time quasi-periodic solutions to nonlinear Schroedinger (NLS) and nonlinear wave equations (NLW) on the torus in arbitrary dimensions. The latter is hyperbolic and uses additionally, a Diophantine property of algebraic numbers.  We mention also a work in progress, on space-time quasi-periodic solutions to non-integrable NLS, whose analysis rests on semi-algebraic geometry.