2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/50352In a classic paper, Fradkin and Tseytlin showed how magnetic deformations can be introduced in open strings. In this contribution we review some recent work on type-I vacua with magnetised branes and describe the role of additional discrete deformations, related to quantised values of the NS-NS antisymmetric tensor B_ab.13 pages. Latex. Contribution to the Conference on ``Quantisation, Gauge Theory, and Strings'' dedicated to the memory of Professor Efim S. FradkinHigh Energy Physics - Theorytext