2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/107298We construct the boundary state describing magnetized D9 branes in R^{3,1} x T^6 and we use it to compute the annulus and Moebius amplitudes. We derive from them, by using open/closed string duality, the number of Landau levels on the torus T^d.12 pages,in honor of Adriano Di Giacomo on his 70th birthday, contribution to the FestschriftHigh Energy Physics - Theorytext