Mixed finite element method for the Poisson equation

The aim of this bachelor thesis is the implementation of the mixed element method for the Poisson equation and the comparison with results of the classical finite element method. The thesis is divided into two chapters. In the first chapter there are descriptions of the spaces occurring in the weak formulation of the Poisson equation and descriptions of the spaces which are suitable to approach them. The second chapter studies the existence of the solutions of the approximated tasks and their convergence. The main part of this thesis are schemes of the solutions of both methods and the tables comparing errors of these solutions for three diferent functions.