Galerkin Method and Optimal Error Algorithms in Hilbert Spaces.
For some variants of the finite element method there exist points having a remainder value or a derivation remainder remarkably less than those given by global norms. This phenomenon is called superconvergence and the points are called superconvergence points. The generalized problem corresponding to (1) is as follows: Let Hk(Ω) be Sobolev space and Hk0(Ω) the completion of the space C∞0(Ω) with norm ∥⋅∥k,Ω. Find u∈H10(Ω) such that for each v∈H10(Ω), (2) a(u,v)=(f,v)0 holds, where a(u,v)=∫Ω(∑n|α|=0aα(x)DαuDαv)dx,...
In the paper, the H^(-1)Galerkin-collocation method with quadratures (instead of integrals) for two point boundary value problems is considered. Approximate solution is a piecewise polynomial of degree r. It is proved that the method is stable and the error in L2-norm is of order O(h^(r+1)) if the used quadrature is exact for polynomial of degree not greater than r+1.
Page 1