We review V.I. Arnold's 1963 celebrated paper [1]
Proof of A.N. Kolmogorov's Theorem on the Conservation of Conditionally Periodic Motions with a Small Variation in the Hamiltonian, and prove that, optimising Arnold's scheme, one can get ''sharp'' asymptotic quantitative conditions (as $\varepsilon \to 0$, $\varepsilon$ being the strength of the perturbation). All constants involved are explicitly computed.
Keywords:
Nearly-integrable Hamiltonian systems, KAM theory, Arnold's Theorem, small divisors, perturbation theory, symplectic transformations
Citation:
Chierchia L., Koudjinan C., V. I. Arnold's “Pointwise” KAM Theorem, Regular and Chaotic Dynamics,
2019, Volume 24, Number 6,
pp. 583-606