A discontinuous Galerkin method with fractal elements

Fuente: arXiv
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Main Authors: Gómez, Sergio, Hewett, David, Moiola, Andrea
Format: Preprint
Published: 2026
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author Gómez, Sergio
Hewett, David
Moiola, Andrea
author_facet Gómez, Sergio
Hewett, David
Moiola, Andrea
contents We formulate, analyse, and implement a discontinuous Galerkin finite element method (DG-FEM) for the approximation of the solution of an elliptic boundary value problem in a domain with fractal boundary. We consider the case of the Poisson equation in the Koch snowflake domain with zero Dirichlet boundary conditions, but our methodology can be generalised to other cases. Rather than first approximating the snowflake domain by a polygonal "prefractal" and then applying a standard DG-FEM on the prefractal, we define a DG-FEM on the snowflake itself, using a geometry-conforming mesh (a fractal tiling) consisting of fractal elements, each similar to the original snowflake. Fluxes across inter-element boundaries, which are fractal curves, are represented in a weak way by integrals over element subdomains. We show how, for local polynomial basis functions, these integrals can be evaluated exactly using the similarity of the elements. We prove well-posedness and quasi-optimality of the method, and provide a partial convergence analysis. We present numerical results for piecewise linear and piecewise quadratic basis functions, which demonstrate the effectiveness of the method. We also apply our method to the related Dirichlet eigenvalue problem.
format Preprint
id arxiv_https___arxiv_org_abs_2604_11093
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle A discontinuous Galerkin method with fractal elements
Gómez, Sergio
Hewett, David
Moiola, Andrea
Numerical Analysis
28A80, 65N30, 65N12, 65N15
We formulate, analyse, and implement a discontinuous Galerkin finite element method (DG-FEM) for the approximation of the solution of an elliptic boundary value problem in a domain with fractal boundary. We consider the case of the Poisson equation in the Koch snowflake domain with zero Dirichlet boundary conditions, but our methodology can be generalised to other cases. Rather than first approximating the snowflake domain by a polygonal "prefractal" and then applying a standard DG-FEM on the prefractal, we define a DG-FEM on the snowflake itself, using a geometry-conforming mesh (a fractal tiling) consisting of fractal elements, each similar to the original snowflake. Fluxes across inter-element boundaries, which are fractal curves, are represented in a weak way by integrals over element subdomains. We show how, for local polynomial basis functions, these integrals can be evaluated exactly using the similarity of the elements. We prove well-posedness and quasi-optimality of the method, and provide a partial convergence analysis. We present numerical results for piecewise linear and piecewise quadratic basis functions, which demonstrate the effectiveness of the method. We also apply our method to the related Dirichlet eigenvalue problem.
title A discontinuous Galerkin method with fractal elements
topic Numerical Analysis
28A80, 65N30, 65N12, 65N15
url https://arxiv.org/abs/2604.11093