Such theory may reproduce the Standard Model at low energies, and hence quark–lepton symmetry may be realized in nature.
neutrino experiments confirm that the Pontecorvo–Maki–Nakagawa–Sakata matrix UPMNS contains large[clarification needed] mixing angles.
The disparity that nature indicates between quark and lepton mixing angles has been viewed in terms of a "quark–lepton complementarity" which can be expressed in the relations Possible consequences of QLC have been investigated in the literature and in particular a simple correspondence between the PMNS and CKM matrices have been proposed and analyzed in terms of a correlation matrix.
Furthermore, in some Grand Unification Theories (GUTs) the direct QLC correlation between the CKM and the PMNS mixing matrix can be obtained.
It is possible to include bimaximal forms of the correlation matrix VM in models with renormalization effects that are relevant, however, only in particular cases with