# Hopf-Andronov-Poincare Bifurcation Case Study

In this section, we shall show that the system (2) undergoes a Hopf-Andronov-Poincare bifurcation by using as a bifurcation real parameter. Without loss of generality, suppose that is a function of and . Then system (2) becomes

(29) with .

System (29) can be written as

(30)

where , and is the bifurcation real parameter. The function is a on an open set in . Let be the set of equilibria of system (29). Suppose that be a sufficiently large open set containing such that for some . We are now interested to vary in order to observe the qualitative changes of solution trajectories near .

Corollary 1. Assume that Theorems [3-7] are hold. Then there is

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For the application of Hopf’s bifurcation theory to the system (29) (see [Marsden J.E., M. Mckracken, 1976]), it is required to satisfy the following transversality condition

(34)

Substituting , and into (31), and calculating the derivatives with respect to , we obtain

(35) where Since , we have , and .

Hence there is a Hopf bifurcation at . We have the following result:

Theorem 13. Suppose holds. Then the system (29) undergoes a Hopf bifurcation when passes through emanating from the steady state leading to periodic solutions trajectories for either (super-critical bifurcation), or (sub-critical-bifurcation) or at .

Next, Hopf bifurcation at :

The Jacobian matrix corresponding to is given by

(36)

where and its nonzero elements are defined as in (14) and (15) with & replaced by & respectively.

The characteristic equation corresponding to obeys

(37)

where the coefficients are defined as in (16).

By the Routh–Hurwitz criteria, all the roots of (37) will have negative real parts if , and

It is required for a Hopf bifurcation that either or must be violated. Suppose such