  In this work, a theorem is first proved which presents a game theoretic
formulation of a necessary and sufficient sustainizability over a set condition
for a general system described by ordinary differential equations (ODEs). Then,
two additional theorems are proved for the n-species Gause-Lotka-Volterra (GLV)
population model, establishing necessary and sufficient sustainability and
sustainizability conditions over rectangular sets. Three case studies on the
May-Leonard, 3-species, GLV model are then presented to illustrate the power of
the above Theorems. In two of these case studies (2 and 3), it is shown that a
particular instance of the 3-species, GLV model is unsustainable but
sustainizable through allowable action.
