2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/57374The paper is devoted to the description of the main geometric and analytic tools of a complex WKB method for adiabatic problem. We illustrate their use by numerous examples.Mathematical PhysicsAnalysis of PDEsSpectral Theory34E05, 34E20, 34L05text