| The paper analyzes a class of predator-prey models and shows the existence of a Hopf Bifurcation point for suitable choice of parameters; global stability is also demonstrated for range of parameter values. This method is then applied to two well known models in economics, viz., Scarf's example of unstable competitive equilibrium and Goodwin's model of growth. It is shown that for suitable parameters both these models have a point of Hopf Bifurcation; further in both models, global stability is demonstrated on one side of the bifurcation point. Thus, for a class of dynamic economic models, the possibility of cyclical behavior around equilibrium is shown to depend crucially on the values of certain parameters. It therefore follows that, the question of how meaningful the cyclical phenomenon is, may be reduced to a question of how meaningful is the range of parameter values for which such phenomenon exists. |