2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/49899We construct a classical field theory action which upon quantization via the functional integral approach, gives rise to a consistent Dirac-string independent quantum field theory. The approach entails a systematic derivation of the correlators of all gauge invariant observables, and also of charged dyonic fields. Manifest SO(2)-duality invariance and Lorentz invariance are ensured by the PST-approach.9 pages, LaTeX, talk given at the conference "Quantum aspects of gauge theories, supersymmetry and unification", Paris, September 1999High Energy Physics - Theorytext