We have a paper detailing the algorithmic approach and the results
when applied to the
Hénon map, at
the classical parameter values:
Algorithms for rigorous entropy bounds and symbolic
dynamics, S. Day, R. Frongillo and R. Trevino, submitted for
publication, 2007.
Below is the image of the index pair for the main result, followed by
the abstract of the paper.
The aim of this paper is to introduce a method for computing rigorous
lower bounds for topological entropy.
topological
entropy. The topological entropy for a
dynamical
system measures the number of trajectories that separate in finite
time and quantifies the complexity of the system. Our method relies on
extending existing computational Conley index techniques for
constructing
semi-conjugate
symbolic
dynamical systems. Besides offering a description of the dynamics,
the constructed symbol system allows for the computation of a lower
bound for the topological entropy of the original system. Our overall
goal is to construct symbolic dynamics that yield a high lower bound
for entropy. The method described in this paper is algorithmic and,
although it is computational, yields mathematically rigorous
results. For illustration, we apply the method to the
Hénon map, where
we compute a rigorous lower bound for topological entropy of 0.4318.