The New Jersey Institute of Technology's
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Title:	Pitchfork bifurcations of invariant manifolds
Author:	Champanerkar, Jyoti
View Online:	njit-etd2004-122 (ix, 60 pages ~ 3.7 MB pdf)
Department:	Department of Mathematical Sciences
Degree:	Doctor of Philosophy
Program:	Mathematical Sciences
Document Type:	Dissertation
Advisory Committee:	Blackmore, Denis L. (Committee chair) Miura, Robert M. (Committee member) Mosher, Lee D. (Committee member) Papageorgiou, Demetrius T. (Committee member) Bose, Amitabha Koshal (Committee member)
Date:	2004-08
Keywords:	Dynamical systems Pitchfork bifurcation Bifurcation Invariant manifolds
Availability:	Unrestricted
Abstract:	In a parameter dependent, dynamical system, when the qualitative structure of the solutions changes due to a small change in the parameter, the system is said to have undergone a bifurcation. Bifurcations have been classified on the basis of the topological properties of fixed points and invariant manifolds of dynamical systems. A pitchfork bifurcation in R is said to have occurred when a stable fixed point becomes unstable and two new stable fixed points, separated by the unstable fixed point come into existence. In this thesis, a pitchfork bifurcation of an (in- 1)-dimensional invariant submani-fold of a dynamical system in Rm is defined analogous to that in R. Sufficient conditions for such a bifurcation to occur are stated and existence of the bifurcated manifolds is shown under the stated hypotheses. The dynamical system is assumed to be a class C1 diffeomorphism or vector field in rtm. The existence of locally attracting invariant manifolds M+ and M- after the bifurcation has taken place, is proved by constructing a diffeomorphism of the unstable manifold M. Techniques used for proving the above mentioned result, involve differential topology and analysis and are adapted from Hartman [18] and Hirsch [19]. The main theorem of the thesis is illustrated by means of a canonical example and applied to a 2-dimensional discrete version of the Lotka-Volterra model, describing dynamics of a predator-prey population. The Lotka-Volterra model is slightly modified to depend on a continuously varying parameter. Significance of a pitchfork bifurcation in the Lotka-Volterra model is discussed with respect to population dynamics. Lastly, implications of the theorem are dicussed from a mathematical point of view.