A characterization of hybridized mixed methods for second order elliptic problems

In this paper, we give a new characterization of the approximate solution given by hybridized mixed methods for second order self-adjoint elliptic problems. We apply this characterization to obtain an explicit formula for the entries of the matrix equation for the Lagrange multiplier unknowns resulting from hybridization. We also obtain necessary and sufficient conditions under which the multipliers of the Raviart-Thomas and the Brezzi-Douglas-Marini methods of similar order are identical.