  We consider the cosmology of modified gravity models in which Newton's
constant is distorted by a function of the inverse d'Alembertian acting on the
Ricci scalar. We derive a technique for choosing the distortion function so as
to fit an arbitrary expansion history. This technique is applied numerically to
the case of LambdaCDM cosmology, and the result agrees well with a simple
hyperbolic tangent.

General Relativity and Quantum Cosmology;Cosmology and Nongalactic Astrophysics;High Energy Physics - Theory