The global and local extrema can be identified by the triality theory.
Jing Liu, Huicheng Liu 2015, 'Canonical Duality for Box Constrained Nonconvex and Nonsmooth Optimization Problems',Mathematical Problems in Engineeringhttp://dx.doi.org/10.1155/2015/354263. Retrieved from DOAJ CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)
Two triality symmetries ensure both dark matter stability and strict lepton number conservation at higher orders.
Cesar Bonilla, Ernest Ma, Eduardo Peinado, Jose W.F. Valle 2016, 'Two-loop Dirac neutrino mass and WIMP dark matter', Physics Letters Bhttp://www.sciencedirect.com/science/article/pii/S0370269316305214. Retrieved from DOAJ CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)