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Groupe de Travail Analyse

Autour du d-bar, épisode 3 - suite et fin

Andreas Hartmann

( IMB )

Salle 1

le 02 octobre 2023 à 14:00

In the previous talks we have seen that in certain problems in complex analysis, one can try to first construct a smooth ((not analytic)) solution to the initial problem with the required properties, which is is in general a rather easy task. In a second step one tries to correct the solution to make it holomorphic maintaining the main properties of the problem: if ff is a smooth solution to the initial problem and if uu is a suitable solution to {\overline{\partial}}\, u=gu=g where g=g={\overline{\partial}\,} ff, then F=fuF=f-u satisfies {\overline{\partial}\,}F=0F=0 so that FF is analytic. The challenge here is that the correction u does not destroy the properties required by the initial problem ((for instance values in given points, norms, etc.)). We have seen different types of problems where this
scheme produces solution ((e.g. interpolation problems, corona/Bézout-type problems, Cousin problem)).

A central tool is Hörmander's theorem which gives the existence of d-bar solutions with norm estimates in suitable weighted spaces, the weight involving subharmonic functions.

The aim of this last talk is to solve an interpolation problem in the Fock space ((which is the space of entire functions square integrable with respect to a gaussian weight)). More precisely, we will show how a certain density condition allows to construct the subharmonic function required by Hörmander's theorem.