Abstract
We prove the existence of geodesics of the weak Riemannian Lie group
(Diff H-infinity(R-n), g(Hk)) = (Diff (R-n) boolean AND (Id + boolean AND(k is an element of N) H-k (R-n; R-n)), g(Hk)),
where g(Hk) is the weak Sobolev metric of order k. Next, we study the Riemannian exponential mapping induced by this metric. For k = I, the result immediately gives the local existence of solution in C-infinity( :H-infinity(R-n:R-n)) of the n-dimensional analog of the Camassa-Holm's equation on the Euclidean space R-n. (C) 2009 Elsevier Masson SAS.