The complexity of nematic liquid crystals has led to the existence of
several major "competing" theories, among which some of the best-known
are: Oseen-Frank (OF),
Ericksen (E) and Landau-de Gennes (LDG).
 The main distinctive feature of the theories is in the different number
of degrees of freedom they use in describing nematic liquid crystals,
namely 2 for OF, 3 for E and 5 for LDG.
 Although the theories essentially agree in their predictions of the
energy minimizers, they seem to substantially disagree
when interpreting the defects patterns.
 A "physical key" toward deciding what should be the right number of
degress of freedom might be contained in the so-called Porod's law,
related to coarsening effects, and we will see how one can attempt to
interpret this mathematically.