Approximation accuracy of Fedorenko finite superelement method in Sobolev spaces

The paper is devoted to the development of Fedorenko finite superelement method (FSEM). A priori error estimates are obtained and the saturability of method is established in S.L. Sobolev spaces. Jackson inequality applying to FSEM approximations is derived. The analysis is carried out on the example of Dirichlet problem, the results can be extended for the class of general linear elliptic problems.