IMA Journal of Numerical Analysis Advance Access published online on March 20, 2008
IMA Journal of Numerical Analysis, doi:10.1093/imanum/drm052
On the norm of the hyperinterpolation operator on the unit disc and its use for the solution of the nonlinear Poisson equation
Department of Mathematics, California State University San Marcos

Departments of Mathematics and Computer Science, The University of Iowa
Department of Mathematics, California State University San Marcos
Email: atkinson{at}math.uiowa.edu
Received on 31 August 2006. Accepted for publication 29 November 2007.
| Abstract |
|---|
In this article, we study the properties of the hyperinterpolation operator on the unit disc D in
. We show how hyperinterpolation can be used in connection with the Kumar–Sloan method to approximate the solution of a nonlinear Poisson equation on the unit disc (discrete Galerkin method). A bound for the norm of the hyperinterpolation operator in the space C(D) is derived. Our results prove the convergence of the discrete Galerkin method in the maximum norm if the solution of the Poisson equation is in the class C1,
(D),
> 0. Finally, we present numerical examples which show that the discrete Galerkin method converges faster than O(n–k), for every
if the solution of the nonlinear Poisson equation is in C
(D).
Key Words: hyperinterpolation operator; discrete Galerkin method; projector norm; nonlinear Poisson equation