Block incremental unknowns for anisotropic elliptic equations Original Research Article

In this article, we define the notion of block incremental unknowns for anisotropic elliptic equations. Written in a block structure, they are nothing more than the classical second order incremental unknowns in one space dimension. In particular, we obtain a priori estimates and we observe a significant gain in the condition number for stiff problems when compared with the classical two-dimensional second order incremental unknowns.