Dirichlet and Neumann Boundary Value Problems for the Polyharmonic Equation in the Unit Ball

In the previous author’s works, a representation of the solution of the Dirichlet boundary value problem for the biharmonic equation in terms of Green’s function is found, and then it is shown that this representation for a ball can be written in the form of the well-known Almansi formula with expli...

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Main Author: Valery Karachik
Format: Article
Language:English
Published: MDPI AG 2021-08-01
Series:Mathematics
Subjects:
Online Access:https://www.mdpi.com/2227-7390/9/16/1907
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author Valery Karachik
author_facet Valery Karachik
author_sort Valery Karachik
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description In the previous author’s works, a representation of the solution of the Dirichlet boundary value problem for the biharmonic equation in terms of Green’s function is found, and then it is shown that this representation for a ball can be written in the form of the well-known Almansi formula with explicitly defined harmonic components. In this paper, this idea is extended to the Dirichlet boundary value problem for the polyharmonic equation, but without invoking the Green’s function. It turned out to find an explicit representation of the harmonic components of the <i>m</i>-harmonic function, which is a solution to the Dirichlet boundary value problem, in terms of <i>m</i> solutions to the Dirichlet boundary value problems for the Laplace equation in the unit ball. Then, using this representation, an explicit formula for the harmonic components of the solution to the Neumann boundary value problem for the polyharmonic equation in the unit ball is obtained. Examples are given that illustrate all stages of constructing solutions to the problems under consideration.
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spelling doaj.art-cca832bf7f2744968767ad790fc85a6f2023-11-22T08:33:42ZengMDPI AGMathematics2227-73902021-08-01916190710.3390/math9161907Dirichlet and Neumann Boundary Value Problems for the Polyharmonic Equation in the Unit BallValery Karachik0Department of Mathematical Analysis, South Ural State University, 454080 Chelyabinsk, RussiaIn the previous author’s works, a representation of the solution of the Dirichlet boundary value problem for the biharmonic equation in terms of Green’s function is found, and then it is shown that this representation for a ball can be written in the form of the well-known Almansi formula with explicitly defined harmonic components. In this paper, this idea is extended to the Dirichlet boundary value problem for the polyharmonic equation, but without invoking the Green’s function. It turned out to find an explicit representation of the harmonic components of the <i>m</i>-harmonic function, which is a solution to the Dirichlet boundary value problem, in terms of <i>m</i> solutions to the Dirichlet boundary value problems for the Laplace equation in the unit ball. Then, using this representation, an explicit formula for the harmonic components of the solution to the Neumann boundary value problem for the polyharmonic equation in the unit ball is obtained. Examples are given that illustrate all stages of constructing solutions to the problems under consideration.https://www.mdpi.com/2227-7390/9/16/1907polyharmonic equationDirichlet problemNeumann problemGreen’s functionAlmansi representation
spellingShingle Valery Karachik
Dirichlet and Neumann Boundary Value Problems for the Polyharmonic Equation in the Unit Ball
Mathematics
polyharmonic equation
Dirichlet problem
Neumann problem
Green’s function
Almansi representation
title Dirichlet and Neumann Boundary Value Problems for the Polyharmonic Equation in the Unit Ball
title_full Dirichlet and Neumann Boundary Value Problems for the Polyharmonic Equation in the Unit Ball
title_fullStr Dirichlet and Neumann Boundary Value Problems for the Polyharmonic Equation in the Unit Ball
title_full_unstemmed Dirichlet and Neumann Boundary Value Problems for the Polyharmonic Equation in the Unit Ball
title_short Dirichlet and Neumann Boundary Value Problems for the Polyharmonic Equation in the Unit Ball
title_sort dirichlet and neumann boundary value problems for the polyharmonic equation in the unit ball
topic polyharmonic equation
Dirichlet problem
Neumann problem
Green’s function
Almansi representation
url https://www.mdpi.com/2227-7390/9/16/1907
work_keys_str_mv AT valerykarachik dirichletandneumannboundaryvalueproblemsforthepolyharmonicequationintheunitball