School ofMathematical and Statistical Sciences

Computational and Applied Math Proseminar

Wednesday, November 9, 12:00 p.m. GWC 487

Jeff Springer

Northern Arizona University

Solutions of Semilinear Elliptic PDEs on Manifolds

Abstract In this talk we introduce the Closest Point Method (CPM) and the Gradient Newton Galerkin Algorithm (GNGA). The Closest Point Method (CPM) is a recent embedding method for solving time-dependent PDE’s on surfaces, which can also easily be utilized to solve eigenvalue problems on surfaces. Implementation of CPM to solve problems on surfaces simplifies possible geometric complications as no prior knowledge of the surface is required, other than it’s closest points. The Gradient Newton Galerkin Algorithm (GNGA) is a method for finding approximations of critical points of a functional. This method was introduced by Neuberger and Swift to solve PDEs of the form Δu + f(u) = 0 on regions Ω with zero Dirichlet boundary conditions. We use GNGA to solve PDEs on manifolds by first finding the eigenfunctions of the Laplacian restricted to the manifold using the CPM. Finally we use a Galerkin expansion, in eigenfunctions of the Laplacian, to find the desired solutions. Examples on basic manifolds will be presented along with suggestions for future work.