Following [6,12], we study coupled map networks over arbitrary finite graphs.
An estimate from below for a topological entropy of a perturbed coupled map
network via a topological entropy of an unperturbed network by making use of
the covering relations for coupled map networks is obtained. The result is
quite general, particularly no assumptions on hyperbolicity of a local dynamics
or linearity of coupling are made.
Let $\{f_{a,b}\}$ be the (original) H\'enon family. In this paper, we show
that, for any $b$ near $0$, there exists a closed interval $J_b$ which contains
a dense subset $J'$ such that, for any $a\in J'$, $f_{a,b}$ has a quadratic
homoclinic tangency associated with a saddle fixed point of $f_{a,b}$ which
unfolds generically with respect to the one-parameter family $\{f_{a,b}\}_{a\in
J_b}$. By applying this result, we prove that $J_b$ contains a residual subset
$A_b^{(2)}$ such that, for any $a\in A_b^{(2)}$, $f_{a,b}$ admits the Newhouse
phenomenon.