TY - JOUR
T1 - Optimal Interior and Local Error Estimates of a Recovered Gradient of Linear Elements on Nonuniform Triangulations
AU - Hlaváček , I.
AU - Křížek , M.
JO - Journal of Computational Mathematics
VL - 4
SP - 345
EP - 362
PY - 1996
DA - 1996/08
SN - 14
DO - http://doi.org/
UR - https://global-sci.org/intro/article_detail/jcm/9244.html
KW - 
AB - <p style="text-align: justify;">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 $d&lt;2q$ 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.</p>