Extrapolation of the Hood-Taylor elements for the Stokes problem (Q1767049)

An extrapolation formula is established which enables to gain one order in the convergence rate of the Hood-Taylor approximation of the Stokes equation on rectangular elements by combining the approximation on a mesh of size \(h\) and a mesh of size \(2h\). An adequate auxiliary problem is introduced in order to get an additional term in the error expansion.