Computation of maximal local (un)stable manifold patches by the parameterization method

In this work we develop some automatic procedures for computing high order polynomial expansions of local (un)stable manifolds for equilibria of differential equations. Our method incorporates validated truncation error bounds, and maximizes the size of the image of the polynomial approximation relative to some specified constraints. More precisely we use that the manifold computations depend heavily on the scalings of the eigenvectors: indeed we study the precise effects of these scalings on the estimates which determine the validated error bounds. This relationship between the eigenvector scalings and the error estimates plays a central role in our automatic procedures. In order to illustrate the utility of these methods we present several applications, including visualization of invariant manifolds in the Lorenz and FitzHugh-Nagumo systems and an automatic continuation scheme for (un)stable manifolds in a suspension bridge problem. In the present work we treat explicitly the case where the eigenvalues satisfy a certain non-resonance condition.Comment: Revised version, typos corrected, references adde

Period doubling in the Rössler system- a computer assisted proof

Using rigorous numerical methods we validate a part of the bifurcation diagram for a Poincaré map of the Rössler system [26]- the existence of two period doubling bifurcations and the existence of a branch of period two points connecting them. Our approach is based on the Lyapunov-Schmidt reduction and uses the C r-Lohner algorithm [31] to obtain rigorous bounds for the Rössler system