1996/04/01 by A. H. Schatz, Ian H. Sloan, I. H. Sloan +2 · 5 citations
Mathematics · Engineering · Computer Science · #Differential Equations and Numerical Methods #Advanced Numerical Methods in Computational Mathematics #Advanced Mathematical Modeling in Engineering
paper · doi:10.1137/0733027
Consider a second-order elliptic boundary value problem in any number of space dimensions with locally smooth coefficients and solution. Consider also its numerical approximation by standard conforming finite element methods with, for example, fixed degree piecewise polynomials on a quasi-uniform mesh-family (the “h-method”). It will be shown that, if the finite element function spaces are locally symmetric about a point x0 with respect to the antipodal map x → x0 - (x - x0 ), then superconvergence ensues at xo under mild conditions on what happens outside a neighborhood of x0 . For piecewise polynomials of even degree, superconvergence occurs in function values; for piecewise polynomials of odd degree, it occurs in derivatives.