Below is the ascii version of the abstract for 14-70.
The html version should be ready soon.
On hyperbolicity in the renormalization
of near-critical area-preserving maps
ABSTRACT. We consider MacKay's renormalization operator
for pairs of area-preserving maps,
near the fixed point obtained in .
Of particular interest is the restriction $R_0$ of this operator
to pairs that commute and have a zero Calabi invariant.
We prove that a suitable extension of $R_0^3$
is hyperbolic at the fixed point, with a single expanding direction.
The pairs in this direction are presumably commuting,
but we currently have no proof for this.
Our analysis yields rigorous bounds on various "universal" quantities,
including the expanding eigenvalue.