Co-authored-by: Wolfgang Bangerth <bangerth@colostate.edu>
<h3>The penalty parameter</h3>
The parameter is defined as $\sigma = \gamma/h_f$, where $h_f$ a local length scale associated
-with the cell face, here we choose the length of the cell in the direction normal to the face,
+with the cell face; here we choose the length of the cell in the direction normal to the face,
and $\gamma$ is the penalization constant.
To ensure the discrete coercivity, the penalization constant has to be large enough @cite ainsworth2007posteriori.
People do not really have consensus on which precise formula to choose, among what was proposed in the literature.
In the beginning the Universe was created. This has made a lot of
people very angry and has been widely regarded as a bad move.
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