On the integrability of the n-centre problem
arXiv:math/0401202
Abstract
It is known that for centres and positive energies the -centre problem of celestial mechanics leads to a flow with a strange repellor and positive topological entropy. Here we consider the energies above some threshold and show: Whereas for arbitrary independent integrals of Gevrey class exist, no real-analytic (that is, Gevrey class 1) independent integral exists.
22 pages, a short announcement see in math.DS/0312429