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Related papers: Finite jet determination of CR embeddings

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In this paper, we study the real hypersurfaces $M$ in $\mathbb C^2$ at points $p\in M$ of infinite type. The degeneracy of $M$ at $p$ is assumed to be the least possible, namely such that the Levi form vanishes to first order in the CR…

Complex Variables · Mathematics 2015-10-21 Peter Ebenfelt , Bernhard Lamel , Dmitri Zaitsev

We classify the Lie algebras of infinitesimal CR automorphisms of weakly pseudoconvex hypersurfaces of finite multitype in $\mathbb C^N$. In particular, we prove that such manifolds admit neither nonlinear rigid automorphisms, nor real or…

Complex Variables · Mathematics 2022-03-23 Shin-Young Kim , Martin Kolar

We construct a finitely dimensional invariant manifold of holomorphic discs attached to a certain class of smooth pseudconvex hypersurfaces of finite type in $\C^2$, generalizing the notion of stationary discs. The discs we construct are…

Complex Variables · Mathematics 2013-08-01 Florian Bertrand , Giuseppe Della Sala

We study the rigidity of holomorphic mappings from a neighborhood of a Levi-nondegenerate CR hypersurface $M$ with signature $l$ into a hyperquadric $Q_{l'}^{N} \subseteq \mathbb{CP}^{N+1}$ of larger dimension and signature. We show that if…

Complex Variables · Mathematics 2010-11-05 Peter Ebenfelt , Ravi Shroff

We study nonlinear automorphisms of Levi degenerate hypersurfaces of finite multitype. By recent results of Kolar, Meylan and Zaitsev, the Lie algebra of infinitesimal CR automorphisms may contain a graded component consisting of nonlinear…

Complex Variables · Mathematics 2015-08-11 Martin Kolar , Francine Meylan

Let C(2,1) be the class of connected 5-dimensional CR-hypersurfaces that are 2-nondegenerate and uniformly Levi degenerate of rank 1. In a recent article, we proved that the CR-structures in C(2,1) are reducible to so(3,2)-valued absolute…

Complex Variables · Mathematics 2014-04-25 Alexander Isaev

The paper gives a complete description of local automorphism groups for Levi degenerate hypersurfaces of finite type in $\mathbb{C}^2$. We also prove that, with the exception of hypersurfaces of the form $v = |z|^k$, local automorphisms are…

Complex Variables · Mathematics 2015-06-26 Martin Kolar

We study CR-manifolds of arbitrary CR codimension, mainly focusing on Levi and contact-nondegeneracy and depth. We investigate these and other invariants in the locally homogeneous case, developing a comprehensive theory which establishes…

Differential Geometry · Mathematics 2026-04-22 Stefano Marini , Costantino Medori , Mauro Nacinovich

We consider the class of Levi nondegenerate hypersurfaces $M$ in $\bC^{n+1}$ that admit a local (CR transversal) embedding, near a point $p\in M$, into a standard nondegenerate hyperquadric in $\Bbb C^{N+1}$ with codimension $k:=N-n$ small…

Complex Variables · Mathematics 2007-05-23 P. Ebenfelt , X. Huang , D. Zaitsev

We consider hypersurfaces of finite type in a direct product space ${\mathbb R}^2 \times {\mathbb R}^2$, which are analogues to real hypersurfaces of finite type in ${\mathbb C}^2$. We shall consider separately the cases where such…

Complex Variables · Mathematics 2016-11-24 Alessandro Ottazzi , Gerd Schmalz

We explicitly determine the structure equations of 5-dimensional Levi 2-nondegenerate CR hypersurfaces, using our recently constructed canonical Cartan connection for this class of CR manifolds. We also give an outline of the basic…

Differential Geometry · Mathematics 2016-03-31 Costantino Medori , Andrea Spiro

We classify polynomial models for real hypersurfaces in $\mathbb C^N$, which admit nonlinearizable infinitesimal CR automorphisms. As a consequence, this provides an optimal 1-jet determination result in the general case. Further we prove…

Complex Variables · Mathematics 2020-04-29 Martin Kolář , Francine Meylan

Germs of locally homogeneous CR manifolds M can be characterized in terms of certain algebraic data, e.g., by CR-algebras. We give an explicit formula which relates the Levi form of such an M and its higher order analogues to the Lie…

Complex Variables · Mathematics 2007-05-23 Gregor Fels

We introduce a class of uniformly $2$-nondegenerate CR hypersurfaces in $\mathbb{C}^N$, for $N>3$, having a rank $1$ Levi kernel. The class is first of all remarkable by the fact that for every $N>3$ it forms an {\em explicit}…

Complex Variables · Mathematics 2024-04-26 Martin Kolář , Ilya Kossovskiy , David Sykes

We provide regularity results for CR-maps between real hypersurfaces in complex spaces of different dimension with a Levi-degenerate target. We address both the real-analytic and the smooth case. Our results allow immediate applications to…

Complex Variables · Mathematics 2020-06-15 Ilya Kossovskiy , Bernhard Lamel , Ming Xiao

The existence of a nondefective stationary disc attached to a nondegenerate model quadric in C^N is a necessary condition to ensure the unique 1-jet determination of the lifts of a key family of stationary discs. In this paper, we give an…

Complex Variables · Mathematics 2021-12-24 Florian Bertrand , Francine Meylan

Let $\mathbb{K}$ be an algebraically closed field of characteristic zero, and $V$ a hypersurface defined by an irreducible polynomial $f$ with coefficients in $\mathbb{K}$ . In this article we prove that an Embedded Deformation of $V$ which…

Algebraic Geometry · Mathematics 2018-06-26 Maximiliano Leyton-Álvarez

It is proved that flatness of an analytic mapping germ from a complete intersection is determined by its sufficiently high jet. As a consequence, one obtains finite determinacy of complete intersections. It is also shown that flatness and…

Complex Variables · Mathematics 2019-08-15 Janusz Adamus , Hadi Seyedinejad

We show that germs of local real-analytic CR automorphisms of a real-analytic hypersurface $M$ in $\C^2$ at a point $p\in M$ are uniquely determined by their jets of some finite order at $p$ if and only if $M$ is not Levi-flat near $p$.…

Complex Variables · Mathematics 2007-05-23 P. Ebenfelt , B. Lamel , D. Zaitsev

Let M be a CR manifold of hypersurface type, which is Levi degenerate but also satisfying a k-nondegeneracy condition at all points. This might be only if dim M is greater than or equal to 5 and if dim M = 5, then k= 2 at all points. We…

Differential Geometry · Mathematics 2013-06-04 Costantino Medori , Andrea Spiro