Models of $2$-nondegenerate CR hypersurface in $\mathbb{C}^N$

Fuente: arXiv
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Hauptverfasser: Gregorovič, Jan, Kolář, Martin, Sykes, David
Format: Preprint
Veröffentlicht: 2024
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author Gregorovič, Jan
Kolář, Martin
Sykes, David
author_facet Gregorovič, Jan
Kolář, Martin
Sykes, David
contents We show that every point in a uniformly $2$-nondegenerate CR hypersurface is canonically associated with a model $2$-nondegenerate structure. The $2$-nondegenerate models are basic CR invariants playing the same fundamental role as quadrics do in the Levi nondegenerate case. We characterize all $2$-nondegenerate models and show that the moduli space of such hypersurfaces in $\mathbb{C}^N$ is infinite dimensional for each $N>3$. We derive a normal form for these models' defining equations that is unique up to an action of a finite dimensional Lie group. We generalize recently introduced CR invariants termed modified symbols, and show how to compute these intrinsically defined invariants from a model's defining equation. We show that these models automatically possess infinitesimal symmetries spanning a complement to their Levi kernel and derive explicit formulas for them.
format Preprint
id arxiv_https___arxiv_org_abs_2404_06525
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Models of $2$-nondegenerate CR hypersurface in $\mathbb{C}^N$
Gregorovič, Jan
Kolář, Martin
Sykes, David
Complex Variables
Differential Geometry
32V05, 32V40, 53C30
We show that every point in a uniformly $2$-nondegenerate CR hypersurface is canonically associated with a model $2$-nondegenerate structure. The $2$-nondegenerate models are basic CR invariants playing the same fundamental role as quadrics do in the Levi nondegenerate case. We characterize all $2$-nondegenerate models and show that the moduli space of such hypersurfaces in $\mathbb{C}^N$ is infinite dimensional for each $N>3$. We derive a normal form for these models' defining equations that is unique up to an action of a finite dimensional Lie group. We generalize recently introduced CR invariants termed modified symbols, and show how to compute these intrinsically defined invariants from a model's defining equation. We show that these models automatically possess infinitesimal symmetries spanning a complement to their Levi kernel and derive explicit formulas for them.
title Models of $2$-nondegenerate CR hypersurface in $\mathbb{C}^N$
topic Complex Variables
Differential Geometry
32V05, 32V40, 53C30
url https://arxiv.org/abs/2404.06525