Super-critical and sub-critical Hopf bifurcations in two and three dimensions

Hopf bifurcations have been studied perturbatively under two broad headings, viz., super-critical and sub-critical. The criteria for occurrences of such bifurcations have been investigated using the renormalization group. The procedure has been described in detail for both two and three dimensions and has been applied to several important models, including those by Lorenz and Rossler.