Prochainement

Pas d'événement prévu ce mois

Passés

Lundi 2 mars 14:00-15:00 Boris Doubrov (Minsk)
Locally homogeneous 5-dimensional real hypersurfaces in C³

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Lieu : IMO ; salle 3L8.

Résumé : We consider the problem of classifying the real hypersurfaces in with transitive symmetry algebra up to the pseudogroup of (local) complex analytic transformations. A similar problem of classifying homogeneous hypersurfaces in C2 was first studied by Élie Cartan and has various applications in differential geometry. Our approach is based on passing to the complexification and first treating the corresponding geometric structures on 5-dimensional complex analytic manifolds, encoding the homogeneous structures by their algebraic data and then passing back to the real case using a combination of algebraic and geometric methods. .

Locally homogeneous 5-dimensional real hypersurfaces in C³  Version PDF
Lundi 24 février 14:00-15:00 Victor Arnaiz (LMO)
Quasimode constructions for perturbed completely integrable systems

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Lieu : IMO ; salle 3L8.

Résumé : In this talk, I will present new results concerning the contruction of quasimodes for perturbed semiclassical harmonic oscillators that exhibit sharp concentration properties. In particular, in the selfadjoint case, we show the existence of quasimodes that concentrate on sets that are invariant by two commuting flows obtained from the perturbation of the system. In the non-selfadjoint case, we test some resolvent estimates near the real axis when no geometric control condition is satisfied. This talk is based on joint works with Fabricio Macià and Gabriel Rivière.

Quasimode constructions for perturbed completely integrable systems  Version PDF