Direct and inverse approximation theorems for the p-version of the finite element method in the framework of weighted Besov spaces, part III: Inverse approximation theorems

This is the third of a series devoted to the direct and inverse approximation theorems of the p-version of the finite element method in the framework of the Jacobi-weighted Besov and Sobolev spaces. In this paper we derive the inverse algebraic approximation in terms of the Jacobi-weighted Besov spaces and prove the inverse theorems for the finite element solutions of the p-version in the Chebyshev-weighted Besov spaces based upon the convergence rate measured in the energy norms.