摘要
The Ritz projections of the elliptic problem（?）(a<sub>ij</sub>（?）<sub>j</sub>u)+c<sub>0</sub>u=f in Ω,u=0 on （?）Ω,and the quasilinear eiliptic problem（?）（a<sub>i</sub>（x,Du））+a<sub>0</sub>（x,Du）=0 in Ω,u=0 on （?）Ωwith linear finite elements admit an asymptotic error expansion,respectively,for certain classes of“uniform” meshes.This provides the theoretical justification for the use of Richardson extrapolationfor increasing the accuracy of the scheme from O（h<sup>2</sup>） to O（h<sup>4</sup> |ln h|）.
The Ritz projections of the elliptic problem(?)(a_(ij)(?)_ju)+c_0u=f in Ω,u=0 on (?)Ω,and the quasilinear eiliptic problem(?)(a_i(x,Du))+a_0(x,Du)=0 in Ω,u=0 on (?)Ωwith linear finite elements admit an asymptotic error expansion,respectively,for certain classes of“uniform” meshes.This provides the theoretical justification for the use of Richardson extrapolationfor increasing the accuracy of the scheme from O(h^2) to O(h^4 |ln h|).
