Second order elliptic systems with Dirichlet boundary conditions are solved by means of affine finite elements on regular uniform triangulations. A simple averagign scheme is proposed, which implies a superconvergence of the gradient. For domains with enough smooth boundary, a global estimate $O(h^{3/2})$ is proved in the $L^2$-norm. For a class of polygonal domains the global estimate $O(h^2)$ can be proven.
@article{104242, author = {Ivan Hlav\'a\v cek and Michal K\v r\'\i \v zek}, title = {On a superconvergent finite element scheme for elliptic systems. I. Dirichlet boundary condition}, journal = {Applications of Mathematics}, volume = {32}, year = {1987}, pages = {131-154}, zbl = {0622.65097}, mrnumber = {0885758}, language = {en}, url = {http://dml.mathdoc.fr/item/104242} }
Hlaváček, Ivan; Křížek, Michal. On a superconvergent finite element scheme for elliptic systems. I. Dirichlet boundary condition. Applications of Mathematics, Tome 32 (1987) pp. 131-154. http://gdmltest.u-ga.fr/item/104242/
Estimates near the boundary for solutions of elliptic partial differential equations satisfying general boundary conditions II, Comm. Pure Appl. Math. 17 (1964), 35-92. (1964) | MR 0162050
Superconvergence of the gradient for linear triangle elements for elliptic and parabolic equations, C. R. Acad. Bulgare Sci. 37 (1984), 293 - 296. (1984) | MR 0758156 | Zbl 0575.65106
The post-processing technique in the finite element method, Parts I-III, Internat. J. Numer. Methods Engrg. 20 (1984), 1085-1109, 1111-1129. (1984)
Optimal points of the stresses for triangular linear element, Numer. Math. J. Chinese Univ. 2 (1980), 12-20. (1980) | MR 0619174 | Zbl 0534.73057
$W^{1,\infty}$-interior estimates for finite element method on regular mesh, J. Comput. Math. 3 (1985), 1-7. (1985) | MR 0815405 | Zbl 0603.34024
The finite element method for elliptic problems, North-Holland, Amsterdam, New York, Oxford, 1978. (1978) | MR 0520174 | Zbl 0383.65058
On the existence and uniqueness of solutions and some variational principles in linear theories of elasticity with couple-stresses, Apl. Mat. 14 (1969), 387-410. (1969) | MR 0250537
Svojstva někotorych klassov differenciruemych funkcij mnogich peremennych, zadannych v n-mernoj oblasti, Trudy Mat. Inst. Steklov. 66 (1962), 227-363. (1962)
Superconvergence phenomenon in the finite element method arising from averaging gradients, Numer. Math. 45 (1984), 105-116. (1984) | Article | MR 0761883
On Superconvergence techniques, Preprint n. 34, Univ. of Jyväskylä, 1984, 1 - 43 (to appear in Acta Appl. Math.). (1984) | MR 0900263
Superconvergent recovery of the gradient from piecewise linear finite element approximations, IMA J. Numer. Anal. 5 (1985), 407-427. (1985) | Article | MR 0816065 | Zbl 0584.65067
Linear finite elements with high accuracy, J. Comput. Math. 3 (1985), 115-133. (1985) | MR 0854355 | Zbl 0577.65094
Acceleration of convergence for finite element solutions of the Poisson equation, Numer. Math. 33 (1979), 43-53. (1979) | Article | MR 0545741 | Zbl 0435.65090
Variational-difference methods for the solution of elliptic equations. Part I, (Proc. Sem., Issue 5, Vilnius, 1973), Inst. of Phys. and Math., Vilnius, 1973, 3-389. (1973)
An investigation of the rate of convergence of variational-difference schemes for second order elliptic equations in a two-dimensional regions with smooth boundary, Ž. Vyčisl. Mat. i Mat. Fiz. 9 (1969), 1102-1120. (1969) | MR 0295599
Variational-difference methods for the solution of elliptic equations, Izd. Akad. Nauk Armjanskoi SSR, Jerevan, 1979. (1979)
Les méthodes directes en théorie des équations elliptiques, Academia, Prague, 1967. (1967) | MR 0227584
On inequalities of Korn's type, Arch. Rational Mech. Anal. 36 (1970), 305-334. (1970) | Article | MR 0252844
Mathematical theory of elastic and elasto-plastic bodies: an introduction, Elsevier, Amsterdam, Oxford, New York, 1981. (1981) | MR 0600655
High order local approximations to derivatives in the finite element method, Math. Соmр. 31 (1977), 652-660. (1977) | MR 0438664
Interior estimates for elliptic systems of difference equations, (Thesis). Univ. of Goteborg, 1982. (1982)
Natural inner Superconvergence for the finite element method, (Proc. China-France Sympos. on the Finite Element method, Beijing, 1982), Science Press, Beijing, Gordon and Breach, New York, 1983, 935-960. (1982) | MR 0754041
Superconvergence and reduced integration in the finite element method, Math. Соmр. 32 (1978), 663-685. (1978) | MR 0495027