Fundamental Solutions and Gegenbauer Expansions of Helmholtz Operators in Riemannian Spaces of Constant Curvature

We perform global and local analysis of oscillatory and damped spherically symmetric fundamental solutions for Helmholtz operators (−Δ±β²) in d-dimensional, R-radius hyperbolic HᵈR and hyperspherical SᵈR geometry, which represent Riemannian manifolds with positive constant and negative constant sect...

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Published in:Symmetry, Integrability and Geometry: Methods and Applications
Date:2018
Main Authors: Cohl, H.S., Dang, T.H., Dunster, T.M.
Format: Article
Language:English
Published: Інститут математики НАН України 2018
Online Access:https://nasplib.isofts.kiev.ua/handle/123456789/209867
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Journal Title:Digital Library of Periodicals of National Academy of Sciences of Ukraine
Cite this:Fundamental Solutions and Gegenbauer Expansions of Helmholtz Operators in Riemannian Spaces of Constant Curvature / H.S. Cohl, T.H. Dang, T.M. Dunster // Symmetry, Integrability and Geometry: Methods and Applications. — 2018. — Т. 14. — Бібліогр.: 37 назв. — англ.

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Digital Library of Periodicals of National Academy of Sciences of Ukraine
id nasplib_isofts_kiev_ua-123456789-209867
record_format dspace
spelling Cohl, H.S.
Dang, T.H.
Dunster, T.M.
2025-11-28T09:33:12Z
2018
Fundamental Solutions and Gegenbauer Expansions of Helmholtz Operators in Riemannian Spaces of Constant Curvature / H.S. Cohl, T.H. Dang, T.M. Dunster // Symmetry, Integrability and Geometry: Methods and Applications. — 2018. — Т. 14. — Бібліогр.: 37 назв. — англ.
1815-0659
2010 Mathematics Subject Classification: 31C12; 32Q45; 33C05; 33C45; 35A08; 35J05; 42A16
arXiv: 1803.07149
https://nasplib.isofts.kiev.ua/handle/123456789/209867
https://doi.org/10.3842/SIGMA.2018.136
We perform global and local analysis of oscillatory and damped spherically symmetric fundamental solutions for Helmholtz operators (−Δ±β²) in d-dimensional, R-radius hyperbolic HᵈR and hyperspherical SᵈR geometry, which represent Riemannian manifolds with positive constant and negative constant sectional curvature, respectively. In particular, we compute closed-form expressions for fundamental solutions of (−Δ±β²) on HᵈR, (−Δ+β²) on SᵈR, and present two candidate fundamental solutions for (−Δ−β²) on SᵈR. Flat-space limits, with their corresponding asymptotic representations, are used to restrict proportionality constants for these fundamental solutions. In order to accomplish this, we summarize and derive new large degree asymptotics for associated Legendre and Ferrers functions of the first and second kind. Furthermore, we prove that our fundamental solutions on the hyperboloid are unique due to their decay at infinity. To derive Gegenbauer polynomial expansions of our fundamental solutions for Helmholtz operators on hyperspheres and hyperboloids, we derive a collection of infinite series addition theorems for Ferrers and associated Legendre functions, which are generalizations and extensions of the addition theorem for Gegenbauer polynomials. Using these addition theorems, in geodesic polar coordinates for dimensions greater than or equal to three, we compute Gegenbauer polynomial expansions for these fundamental solutions, and azimuthal Fourier expansions in two dimensions.
We thank George Pogosyan and Loyal Durand for valuable discussions, and the referees for many helpful suggestions. T.M.D. acknowledges support from Ministerio de Economía y Competitividad, Spain, project MTM2015-67142-P (MINECO/FEDER, UE).
en
Інститут математики НАН України
Symmetry, Integrability and Geometry: Methods and Applications
Fundamental Solutions and Gegenbauer Expansions of Helmholtz Operators in Riemannian Spaces of Constant Curvature
Article
published earlier
institution Digital Library of Periodicals of National Academy of Sciences of Ukraine
collection DSpace DC
title Fundamental Solutions and Gegenbauer Expansions of Helmholtz Operators in Riemannian Spaces of Constant Curvature
spellingShingle Fundamental Solutions and Gegenbauer Expansions of Helmholtz Operators in Riemannian Spaces of Constant Curvature
Cohl, H.S.
Dang, T.H.
Dunster, T.M.
title_short Fundamental Solutions and Gegenbauer Expansions of Helmholtz Operators in Riemannian Spaces of Constant Curvature
title_full Fundamental Solutions and Gegenbauer Expansions of Helmholtz Operators in Riemannian Spaces of Constant Curvature
title_fullStr Fundamental Solutions and Gegenbauer Expansions of Helmholtz Operators in Riemannian Spaces of Constant Curvature
title_full_unstemmed Fundamental Solutions and Gegenbauer Expansions of Helmholtz Operators in Riemannian Spaces of Constant Curvature
title_sort fundamental solutions and gegenbauer expansions of helmholtz operators in riemannian spaces of constant curvature
author Cohl, H.S.
Dang, T.H.
Dunster, T.M.
author_facet Cohl, H.S.
Dang, T.H.
Dunster, T.M.
publishDate 2018
language English
container_title Symmetry, Integrability and Geometry: Methods and Applications
publisher Інститут математики НАН України
format Article
description We perform global and local analysis of oscillatory and damped spherically symmetric fundamental solutions for Helmholtz operators (−Δ±β²) in d-dimensional, R-radius hyperbolic HᵈR and hyperspherical SᵈR geometry, which represent Riemannian manifolds with positive constant and negative constant sectional curvature, respectively. In particular, we compute closed-form expressions for fundamental solutions of (−Δ±β²) on HᵈR, (−Δ+β²) on SᵈR, and present two candidate fundamental solutions for (−Δ−β²) on SᵈR. Flat-space limits, with their corresponding asymptotic representations, are used to restrict proportionality constants for these fundamental solutions. In order to accomplish this, we summarize and derive new large degree asymptotics for associated Legendre and Ferrers functions of the first and second kind. Furthermore, we prove that our fundamental solutions on the hyperboloid are unique due to their decay at infinity. To derive Gegenbauer polynomial expansions of our fundamental solutions for Helmholtz operators on hyperspheres and hyperboloids, we derive a collection of infinite series addition theorems for Ferrers and associated Legendre functions, which are generalizations and extensions of the addition theorem for Gegenbauer polynomials. Using these addition theorems, in geodesic polar coordinates for dimensions greater than or equal to three, we compute Gegenbauer polynomial expansions for these fundamental solutions, and azimuthal Fourier expansions in two dimensions.
issn 1815-0659
url https://nasplib.isofts.kiev.ua/handle/123456789/209867
citation_txt Fundamental Solutions and Gegenbauer Expansions of Helmholtz Operators in Riemannian Spaces of Constant Curvature / H.S. Cohl, T.H. Dang, T.M. Dunster // Symmetry, Integrability and Geometry: Methods and Applications. — 2018. — Т. 14. — Бібліогр.: 37 назв. — англ.
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AT dunstertm fundamentalsolutionsandgegenbauerexpansionsofhelmholtzoperatorsinriemannianspacesofconstantcurvature
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