2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/75503For semiclassical problems we establish upper bounds on the number of resonances in boxes of size $h$ along the real axis, in terms of the dimension of the set of trapped trajectories. The proof uses second microlocalization.Spectral TheoryAnalysis of PDEs35P20; 35S05; 35B34text