Let f be a C∞ Anosov
diffeomorphism of a compact manifold M, preserving a smooth measure. If f satisfies
the - pinching assumption defined below, it must preserve a continuous affine
connection for which the leaves of the Anosov foliations are totally geodesic,
geodesically complete, and flat (its tangential curvature is defined along individual
leaves). If this connection, which is the unique f-invariant affine connection on M, is
Cr-differentiable, r ≥ 2, then f is conjugate via a Cr+2-affine diffeomorphism to a
hyperbolic automorphism of a geodesically complete flat manifold. If f preserves
a smooth symplectic form, has C3 Anosov foliations, and satisfies the 2 :
1-nonresonance condition (an assumption that is weaker than pinching), then f is
C∞ conjugate to a hyperbolic automorphism of a complete flat manifold. (In the
symplectic case, the invariant connection is the one previously defined by
Kanai in the context of geodesic flows.) If the foliations are C2 and the
holonomy pseudo-groups satisfy a certain growth condition, the same conclusion
holds.