  We show that there is a minimal discrete symmetry which leads to the extended
flavour democracy scenario constraining the Dirac neutrino, the charged lepton
and the Majorana neutrino mass term ($M_R$) to be all proportional to the
democratic matrix, with all elements equal. In particular, this discreet
symmetry forbids other large contributions to $M_R$, such as a term
proportional to the unit matrix, which would normally be allowed by a
$S_{3L}\times S_{3R}$ permutation symmetry. This feature is crucial in order to
obtain large leptonic mixing, without violating 't Hooft's, naturalness
principle.

High Energy Physics - Phenomenology