DUALITY AND GLOBAL SYMMETRIES

Duality symmetries are reviewed. A sufficient condition for duality is the existence of a global symmetry. This can be used as a guideline t o systematically prove duality between different field theories. Boson ization and T-duality, for abelian and non-abelian global symmetries, are discussed in detail as well as duality for general antisymmetric t ensor field theories. In this case, the presence of topological defect s break the global symmetry but duality survives manifesting itself in a different way. Open questions end current limitations of this appro ach to prove all known dualities are discussed.