@Article{JCM-14-4, author = {I., Hlaváček and M., Křížek}, title = {Optimal Interior and Local Error Estimates of a Recovered Gradient of Linear Elements on Nonuniform Triangulations}, journal = {Journal of Computational Mathematics}, year = {1996}, volume = {14}, number = {4}, pages = {345--362}, abstract = {
We examine a simple averaging formula for the gradient of linear finite elements in $R^d$ whose interpolation order in the $L^q$-norm is $O(h^2)$ for $d<2q$ and nonuniform triangulations. For elliptic problems in $R^2$ we derive an interior superconvergence for the averaged gradient over quasiuniform triangulations. Local error estimates up to a regular part of the boundary and the effect of numerical integration are also investigated.
}, issn = {1991-7139}, doi = {https://doi.org/1996-JCM-9244}, url = {https://global-sci.com/article/85800/optimal-interior-and-local-error-estimates-of-a-recovered-gradient-of-linear-elements-on-nonuniform-triangulations} }