  A minimal flavour violation hypothesis for leptons can be implemented
essentially in two ways that are compatible with a type-I seesaw structure with
three heavy singlet neutrinos $N$, and that satisfy the requirement of being
predictive, in the sense that all lepton flavor violating (LFV) effects can be
expressed in terms of low energy observables. The first realization is CP
conserving and is based on the flavor group $SU(3)_e\times SU(3)_\ell\times
O(3)_N$ (being $e$ and $\ell$ the SU(2) singlet and doublet leptons). The
second realization allows for CP violation and is based on $SU(3)_e\times
SU(3)_{\ell+N}$. I review the main features of the two schemes and point out
their different implications for LFV observables.
