* @sect3{Implementation}
*
* In principle, the implementation of the error estimation is simple: let
- * $$ \eta_K^2 =
- * \frac h{24} \int_{\partial K} \left[a \frac{\partial u_h}{\partial n}\right]^2 do
- * $$
+ * \f[
+ * \eta_K^2 = \frac h{24} \int_{\partial K} \left[a \frac{\partial u_h}{\partial n}\right]^2 do
+ * \f]
* be the error estimator for cell $K$. $[\cdot]$ denotes the jump of the
* argument at the face. In the paper of Ainsworth, $h$ is divided by $24$,
* but this factor is a bit esoteric, stemming from interpolation estimates
*
* @item The face belongs to a Neumann boundary. In this case, the
* contribution of the face $F\in\partial K$ looks like
- * $$ \int_F \left|g-a\frac{\partial u_h}{\partial n}\right|^2 ds $$
+ * \f[ \int_F \left|g-a\frac{\partial u_h}{\partial n}\right|^2 ds \f]
* where $g$ is the Neumann boundary function. If the finite element is
* vector-valued, then obviously the function denoting the Neumann boundary
* conditions needs to be vector-valued as well.