Envelope of Holomorphy of Matsuki Orbits in Complex Grassmannians

Fuente: arXiv
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Auteur principal: Ullah, Irfan
Format: Preprint
Publié: 2025
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author Ullah, Irfan
author_facet Ullah, Irfan
contents We study the envelopes of holomorphy of Matsuki orbits $M_{\ell,m,r}$ arising as intersections of $G_0$- and $K$-orbits in complex Grassmannians. These orbits, equipped with natural CR-structures, form a class of compact homogeneous CR-submanifolds whose analytic continuation properties are of fundamental interest. Building on Rossi's theory of holomorphic extension, we establish that the envelope of holomorphy of each Matsuki orbit coincides biholomorphically with the containing $K$-orbit $O_{\ell,m}$. Our approach provides a geometric proof based on the holomorphic fiber bundle structure $π: M_{\ell,m,r} \to \mathrm{Gr}_{\ell}(E_+) \times \mathrm{Gr}_{m}(E_-)$, clarifying the role of compact isotropic fibers in constraining holomorphic extension. Explicit examples, including the orbit $M_{1,1,1} \subset \mathrm{Gr}_3(\mathbb{C}^8)$, illustrate the method and highlight connections with classical constructions in complex geometry and representation theory.
format Preprint
id arxiv_https___arxiv_org_abs_2509_17001
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Envelope of Holomorphy of Matsuki Orbits in Complex Grassmannians
Ullah, Irfan
Representation Theory
Algebraic Geometry
Complex Variables
Differential Geometry
22E46, 32V35, 32M10
We study the envelopes of holomorphy of Matsuki orbits $M_{\ell,m,r}$ arising as intersections of $G_0$- and $K$-orbits in complex Grassmannians. These orbits, equipped with natural CR-structures, form a class of compact homogeneous CR-submanifolds whose analytic continuation properties are of fundamental interest. Building on Rossi's theory of holomorphic extension, we establish that the envelope of holomorphy of each Matsuki orbit coincides biholomorphically with the containing $K$-orbit $O_{\ell,m}$. Our approach provides a geometric proof based on the holomorphic fiber bundle structure $π: M_{\ell,m,r} \to \mathrm{Gr}_{\ell}(E_+) \times \mathrm{Gr}_{m}(E_-)$, clarifying the role of compact isotropic fibers in constraining holomorphic extension. Explicit examples, including the orbit $M_{1,1,1} \subset \mathrm{Gr}_3(\mathbb{C}^8)$, illustrate the method and highlight connections with classical constructions in complex geometry and representation theory.
title Envelope of Holomorphy of Matsuki Orbits in Complex Grassmannians
topic Representation Theory
Algebraic Geometry
Complex Variables
Differential Geometry
22E46, 32V35, 32M10
url https://arxiv.org/abs/2509.17001