2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/170917On the occasion of the 40-th anniversary of IHES I present a few scientific reminiscences: most of my scientific life has been marked by my visits and I run through them concluding with the analysis of a problem that originated during my last visit. The problem is to develop a convergent perturbative algorithm for the construction of the ``Eliasson's potential'' for the stable and unstable manifolds of an invariant torus: and to study its properties. A brief review follows.70 Kb; 15 pages, plain TeX, 3 figuresChaotic Dynamicstext