Published online by Cambridge University Press: 20 June 2017
We show that a $C^{1}$-generic non-partially hyperbolic symplectic diffeomorphism
$f$ has topological entropy equal to the supremum of the sum of the positive Lyapunov exponents of its hyperbolic periodic points. Moreover, we also prove that
$f$ has topological entropy approximated by the topological entropy of
$f$ restricted to basic hyperbolic sets. In particular, the topological entropy map is lower semicontinuous in a
$C^{1}$-generic set of symplectic diffeomorphisms far from partial hyperbolicity.