Q

Here, u ∈ V denotes the solution of the continuous variational problem. In a strict sense, the constantC > 0 must not depend on the choice of Vh. In a loose sense, it may depend on the family of finite elements, but not on the triangulation, on whichVh is built. In a very loose sense, if families of triangulations are involved, one demands that the constant C be independent of the mesh width, but it may depend on shape regularity.