2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/62750For a class of non-selfadjoint h-pseudodifferential operators in dimension 2, we determine all eigenvalues in an h-independent domain in the complex plane and show that they are given by a Bohr-Sommerfeld quantization condition. No complete integrability is assumed, and as a geometrical step in our proof, we get a KAM-type theorem (without small divisors) in the complex domain.Spectral TheoryMathematical Physics31C10; 35P05; 37J40; 37K05; 47J20; 58J52text