AMMCS2013 Venue: Wilfrid Laurier
University Campus in Waterloo, Canada 




AMMCS2013 SemiPlenary Talk
Boundary Conditions for Constrained Hyperbolic Systems: Mathematical and
Numerical Analysis
Nicolae Tarfulea (Purdue University Calumet)
Abstract:
Many applications in sciences and technology lead to first order symmetric hyperbolic (FOSH) systems of differential equations supplemented by constraint equations. The Cauchy problem for many such FOSH systems is
constraintpreserving, i.e., the solution satis?es certain spatial differential constraints whenever the initial data does
(e.g., Maxwell's equations or Einstein's field equations in various FOSH formulations). Frequently, artificial space
cut offs are performed for such evolution systems, usually out of the necessity for finite computational domains.
However, it may easily happen that boundary conditions at the artficial boundary for such a system lead to an
initial boundary value problem which, while wellposed, does not preserve the constraints. Therefore, boundary
conditions have to be posed in such a way that the numerical solution of the cut off system approximates as best
as possible the solution of the original problem on infinite space, and this includes the preservation of constraints.
It has become increasingly clear that in order for constraints to be preserved during evolution, the boundary conditions have to be chosen in an appropriate way. Here we consider the problem of finding constraintpreserving
boundary conditions for constrained FOSH systems in the wellposed class of maximal nonnegative boundary
conditions. Based on a characterization of maximal nonnegative boundary conditions, we discuss a systematic
technique for finding such boundary conditions that preserve the constraints, pending that the constraints satisfy a
FOSH system themselves. We exemplify this technique by presenting a few relevant applications (e.g., for FOSH
formulations of Einstein's equations and for systems of wave equations in FOSH formulation subject to divergence
constraints).
Dr Nicolae Tarfulea is Associate Professor in the
Department of Mathematics, Computer Science & Statistics,
Purdue University Calumet.
He received his PhD from the University of Minnesota and his M.S. in Mathematics from the Penn State University in 2004 and 2001, respectively. His main research Interests are in
Partial Differential Equations; Numerical Analysis; General Relativity.
More precisely: boundary conditions for hyperbolic formulations of Einstein's equations, nonlinear elliptic equations,
reaction diffusion systems, compressed sensing, and finite element methods.
He has published 23 papers on these subjects in some of the most prestigious journals of mathematics,
and gave over 20 invited talks in the last five years, and been a part of six research grants.
