The Picard group of the moduli of G-bundles on a curve

This paper is concerned with the moduli space of principal G-bundles on an algebraic curve, for G a complex semi-simple group. While the case G = SL r , which corresponds to vector bundles, has been extensively studied in algebraic geometry, the general case has attracted much less attention until recently, when it became clear that these spaces play an important role in Quantum Field Theory. In particular, if L is a holomorphic line bundle on the moduli space MG , the space