“…Consider y = (q 1 , q 2 , q ′ 1 , q ′ 2 ) the exact solution of (24) where we assume that the vector fields g 1 , g 2 have the regularity C p+1 . Consider ϕ ε the flow map with time ε of (10)- (25) where η = ε is fixed, and Ψ N,H a MRCM (7) satisfying the hypotheses of Theorem 2.6. Then, there exist C, H 0 > 0 such that for all H ≤ H 0 , N ≥ 2s, and mH ≤ T ,…”