For homonymous articles, see Goursat, Levi and Civita (disambiguation). This article is a draft on mechanics.
You can share your knowledge by improving it (how?) according to the recommendations of the corresponding projects.
The theorem is demonstrated by Goursat (1889) for the bicentenary of the Principia. Tullio Levi-Civita will take it back (1903) for questions of disturbances in celestial mechanics.
It will be amply repeated and developed by an article by Arnold and Needham.
We can transmute a central field in -r ^ p into a central field in - 1 / r ^ n in the involutionary relation (3+n)(3-p) = 4. Demonstrationchange code
It implies a change in the time scale. code
wiki
