When the derivative changes from positive to negative, you have a local min, which doubles as a POSSIBLE absolute min. When the derivate changes from negative to positive, you have a local max, which doubles as a possible absolute max. Do not forget that both en...
Soforanon-degeneratecriticalpoint,ifitsMI=0,thenitisalocalminimizerandastable solution,andifitsMI>0,thenitisamin-maxtypeand unstable solution. Multiple solutions with different performance and instability exist in many nonlinear problems in natural and social sciences [20, 18, 14, 22, 13]. Stabil...