Cartan uniqueness theorem on nonopen sets

Fuente: arXiv
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Main Authors: Lebl, Jiri, Noell, Alan, Ravisankar, Sivaguru
Format: Preprint
Published: 2021
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_version_ 1866915159305355264
author Lebl, Jiri
Noell, Alan
Ravisankar, Sivaguru
author_facet Lebl, Jiri
Noell, Alan
Ravisankar, Sivaguru
contents Cartan's uniqueness theorem does not hold in general for CR mappings, but it does hold under certain conditions guaranteeing extendibility of CR functions to a fixed neighborhood. These conditions can be defined naturally for a wide class of sets such as local real-analytic subvarieties or subanalytic sets, not just submanifolds. Suppose that $V$ is a locally connected and locally closed subset of ${\mathbb{C}}^n$ such that the hull constructed by contracting analytic discs close to arbitrarily small neighborhoods of a point always contains the point in the interior. Then restrictions of holomorphic functions uniquely extend to a fixed neighborhood of the point. Using this extension, we obtain a version of Cartan's uniqueness theorem for such sets. When $V$ is a real-analytic subvariety, we can generalize the concept of infinitesimal CR automorphism and also prove an analogue of the theorem. As an application of these two results we show that, for circular subvarieties satisfying the condition, the only automorphisms, CR or infinitesimal, are linear.
format Preprint
id arxiv_https___arxiv_org_abs_2112_07585
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle Cartan uniqueness theorem on nonopen sets
Lebl, Jiri
Noell, Alan
Ravisankar, Sivaguru
Complex Variables
32H02 (Primary), 32V40 32B20 (Secondary)
Cartan's uniqueness theorem does not hold in general for CR mappings, but it does hold under certain conditions guaranteeing extendibility of CR functions to a fixed neighborhood. These conditions can be defined naturally for a wide class of sets such as local real-analytic subvarieties or subanalytic sets, not just submanifolds. Suppose that $V$ is a locally connected and locally closed subset of ${\mathbb{C}}^n$ such that the hull constructed by contracting analytic discs close to arbitrarily small neighborhoods of a point always contains the point in the interior. Then restrictions of holomorphic functions uniquely extend to a fixed neighborhood of the point. Using this extension, we obtain a version of Cartan's uniqueness theorem for such sets. When $V$ is a real-analytic subvariety, we can generalize the concept of infinitesimal CR automorphism and also prove an analogue of the theorem. As an application of these two results we show that, for circular subvarieties satisfying the condition, the only automorphisms, CR or infinitesimal, are linear.
title Cartan uniqueness theorem on nonopen sets
topic Complex Variables
32H02 (Primary), 32V40 32B20 (Secondary)
url https://arxiv.org/abs/2112.07585