2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/29063Semi-flexible manifolds such as fluid membranes or semi-flexible polymers undergo delocalization transitions if they are subject to attractive interactions. We study manifolds with short-ranged interactions by field-theoretic methods based on the operator product expansion of local interaction fields. We apply this approach to manifolds in a random potential. Randomness is always relevant for fluid membranes, while for semi-flexible polymers there is a first order transition to the strong coupling regime at a finite temperature.4 pages including 2 figures; some corrections of the perturbation theorySoft Condensed MatterStatistical Mechanicstext