Iterated Petrov–Galerkin Method with Regular Pairs for Solving Fredholm Integral Equations of the Second Kind

In this work we obtain approximate solutions for Fredholm integral equations of the second kind by means of Petrov–Galerkin method, choosing “regular pairs” of subspaces, Xn,Yn, which are simply characterized by the positive definitiveness of a correlation matrix. This choice guarantees the solvabil...

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Main Authors: Silvia Alejandra Seminara, María Inés Troparevsky
Format: Article
Language:English
Published: MDPI AG 2018-11-01
Series:Mathematical and Computational Applications
Subjects:
Online Access:https://www.mdpi.com/2297-8747/23/4/73
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author Silvia Alejandra Seminara
María Inés Troparevsky
author_facet Silvia Alejandra Seminara
María Inés Troparevsky
author_sort Silvia Alejandra Seminara
collection DOAJ
description In this work we obtain approximate solutions for Fredholm integral equations of the second kind by means of Petrov–Galerkin method, choosing “regular pairs” of subspaces, Xn,Yn, which are simply characterized by the positive definitiveness of a correlation matrix. This choice guarantees the solvability and numerical stability of the approximation scheme in an easy way, and the selection of orthogonal basis for the subspaces make the calculations quite simple. Afterwards, we explore an interesting phenomenon called “superconvergence”, observed in the 1970s by Sloan: once the approximations un∈Xn to the solution of the operator equation u-Ku=g are obtained, the convergence can be notably improved by means of an iteration of the method, un*=g+Kun. We illustrate both procedures of approximation by means of two numerical examples: one for a continuous kernel, and the other for a weakly singular one.
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spelling doaj.art-e6f341bb10d447f7a55a609e021c9af72022-12-21T23:30:52ZengMDPI AGMathematical and Computational Applications2297-87472018-11-012347310.3390/mca23040073mca23040073Iterated Petrov–Galerkin Method with Regular Pairs for Solving Fredholm Integral Equations of the Second KindSilvia Alejandra Seminara0María Inés Troparevsky1Departamento de Matemática, Facultad de Ingeniería, Universidad de Buenos Aires, C1063ACV Buenos Aires, ArgentinaDepartamento de Matemática, Facultad de Ingeniería, Universidad de Buenos Aires, C1063ACV Buenos Aires, ArgentinaIn this work we obtain approximate solutions for Fredholm integral equations of the second kind by means of Petrov–Galerkin method, choosing “regular pairs” of subspaces, Xn,Yn, which are simply characterized by the positive definitiveness of a correlation matrix. This choice guarantees the solvability and numerical stability of the approximation scheme in an easy way, and the selection of orthogonal basis for the subspaces make the calculations quite simple. Afterwards, we explore an interesting phenomenon called “superconvergence”, observed in the 1970s by Sloan: once the approximations un∈Xn to the solution of the operator equation u-Ku=g are obtained, the convergence can be notably improved by means of an iteration of the method, un*=g+Kun. We illustrate both procedures of approximation by means of two numerical examples: one for a continuous kernel, and the other for a weakly singular one.https://www.mdpi.com/2297-8747/23/4/73Fredholm integral equationsnumerical solutionsPetrov–Galerkin methodregular pairsiterated methods
spellingShingle Silvia Alejandra Seminara
María Inés Troparevsky
Iterated Petrov–Galerkin Method with Regular Pairs for Solving Fredholm Integral Equations of the Second Kind
Mathematical and Computational Applications
Fredholm integral equations
numerical solutions
Petrov–Galerkin method
regular pairs
iterated methods
title Iterated Petrov–Galerkin Method with Regular Pairs for Solving Fredholm Integral Equations of the Second Kind
title_full Iterated Petrov–Galerkin Method with Regular Pairs for Solving Fredholm Integral Equations of the Second Kind
title_fullStr Iterated Petrov–Galerkin Method with Regular Pairs for Solving Fredholm Integral Equations of the Second Kind
title_full_unstemmed Iterated Petrov–Galerkin Method with Regular Pairs for Solving Fredholm Integral Equations of the Second Kind
title_short Iterated Petrov–Galerkin Method with Regular Pairs for Solving Fredholm Integral Equations of the Second Kind
title_sort iterated petrov galerkin method with regular pairs for solving fredholm integral equations of the second kind
topic Fredholm integral equations
numerical solutions
Petrov–Galerkin method
regular pairs
iterated methods
url https://www.mdpi.com/2297-8747/23/4/73
work_keys_str_mv AT silviaalejandraseminara iteratedpetrovgalerkinmethodwithregularpairsforsolvingfredholmintegralequationsofthesecondkind
AT mariainestroparevsky iteratedpetrovgalerkinmethodwithregularpairsforsolvingfredholmintegralequationsofthesecondkind