arXiv subjects
Publications and source records attributed to Herve Gaussier.
The Kohn-Nireberg domains are unbounded domains in the complex Euclidean space of dimension 2 upon which many outstanding questions are yet to be explored. The primary aim of this article is to demonstrate that the Bergman and Caratheodory metrics of any Kohn-Nirenberg domains are positive and complete.
We prove that Kobayashi isometries between strongly convex domains are holomorphic or anti-holomorphic. More precisely, let $n_1, n_2$ be positive integers and let $Ω_i \subset \C^{n_i}, \ i=1,2$, be bounded $C^3$ strongly convex domains. If $ϕ: (Ω_1, d^K_{Ω_1}) \rightarrow (Ω_2, d^K_{Ω_2})$ is an isometry, i.e. $ d^K_Ω_{n_2}(f(ζ),f(η)) = d^K_{n_1} (ζ,η)$ for all $ζ,η\in Ω_1,$ then $ϕ$ is either holomorphic or anti-holomorphic.
We give a characterization of the complex Euclidean space C^n, proving a global Newlander-Nirenberg's theorem on the representability of complex structures close to the standard complex structure on C^n.
We present some results dealing with the local geometry of almost complex manifolds. We establish mainly the complete hyperbolicity of strictly pseudoconvex domains, the extension of plurisubharmonic functions through generic submanifolds and the elliptic regularity of some diffeomorphisms in almost complex manifolds with boundary.
We prove that the local (pseudo)group of biholomorphisms stabilizing a minimal, finitely nondegenerate real algebraic submanifold in C^n is a real algebraic local Lie group (the works of S.M. Baouendi, P. Ebenfelt, L.-P. Rothschild and D. Zaitsev published in this direction restrict, without understandable reason, to the isotropy group of a fixed central point). We deduce necessary conditions for the local algebraizability of real analytic rigid tubes of arbitrary codimension in C^n. Without using the Elie Cartan equivalence algorithm, we explain the up to now only known example Im w = e^(|z^2|), due to X. Huang, S. Ji and S.S. Yau in 2001, of a nonalgebraizable Levi nondegenerate real analytic hypersurface of C^2. These elementary criteria provide a first answer to an open problem raised by S.M. Baouendi, P. Ebenfelt and L.-P. Rothschild, in the survey article : ``Local geometric properties of real submanifolds in complex space'', Bull. Amer. Math. Soc. (N.S.) 37 (2000), no. 3, 309--336. A second answer (necessary and sufficient condition) for local algebraizability in the homogeneous case will appear subsequently.
We give a necessary and sufficient condition for the smooth extension of a diffeomorphism between smooth strictly pseudoconvex domains in four real dimensional almost complex manifolds. The proof is mainly based on a reflection principle for pseudoholomorphic discs, on precise estimates of the Kobayashi-Royden infinitesimal pseudometric and on the scaling method in almost complex manifolds.