These are the 8 papers in the [BS] series
The first of these papers is [BS1], which defines the invariant currents,
as well as the invariant measure, and it gives the basic structure of Hénon maps in the hyperbolic case. We think of
this invariant measure as "the" invariant measure because it is just given to us "for free" since it is the
equilibrium measure of the invariant set K
(or, equivalently, as the equilibrium measure of J). You can look at
[BT1] for a longer discussion of the
"equilibrium measure" of a compact subset of Cn.
[BS2] gives the convergence to
the invariant current. For instance, the normalized pullbacks of a stable disk converge to the
stable current. As a consequence, every stable manifold is dense in J+.
The paper [BS3] shows that the invariant measure
is mixing and has entropy log(d). Further, the Lyapunov exponents of the invariant measure
are nonzero (in fact, their absolute values are at least log(d)>0), and thus the invariant measure is hyperbolic.
In collaboration with Misha Lyubich, we characterized "the" invariant measure as the unique measure
of maximal entropy. This paper introduces the measure-theoretic sense of "laminar currents", which was
subsequently re-done much better by Dujardin in three papers:
structure of currents,
intersection of currents.
Among the things that these papers do is to give more general settings in which we can conclude that a
current is laminar. Also, they give a more clear understanding of the connection
between the (easier?) "analytic" intersection product
as defined in [BT1]
and the (more subtle?) "geometric" intersection product. The ability to identify these two sorts of intersection
product is an important technical tool.
This paper also shows that "the" invariant measure gives the limiting distribution of the saddle points.
The paper [BS5] defines critical points both in the
escaping locus U+ and in the intersection of U+ and
U-. It shows that, in the 2nd case, the critical locus is never empty; and in the
first case, it defines the "critical measure" and gives an integral formula for the Lyapunov exponent
in terms of the Green function G+ and the critical measure. The Lyapunov exponent
is equal to log(d) if and only if the critical measure is zero.
[BS6] discusses the connectivity of J. For
instance, J is connected if and only if each unstable slice of K+ is connected.
Equivalently, iff there are no critical points in the unstable slice. Equivalently, J is connected
if and only if the Lyapunov exponent is log(d).
The theory of external rays are developed in [BS7].
If J is connected and hyperbolic, then J+ is essentially a complex solenoid.
This allows us to define external rays land show that they land continuously in this case. This shows
that when J is hyperbolic and connected, it is also a finite quotient of the real solenoid. This
is the 2-dimensional counterpart to the 1-dimensional result which says that if a polynomial Julia set
is hyperbolic and connected, then it is a finite quotient of the circle.
[BS8] introduces quasi-expanding
and quasi-hyperbolic maps. Since all real Hénon maps of (maximal) entropy log(d)
are shown to be quasi-hyperbolic, his paper is the foundation for our work on real maps of
maximal entropy, which includes the case of real horseshoes.
Expository paper with a focus on "external rays"
Real and complex horseshoes
Click here for the page on real and complex horseshoes
This is the paper [BSU] on parabolic
implosion written with John Smillie and Tetsuo Ueda. It is a revision of the earlier version which
we put on the arXiv; we couldn't put this revision on the arXiv because the graphics files are too
big. I hope you will read the paper and enjoy the pictures.
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