EXACT SEQUENCES FOR THE GALOIS GROUP

When F : C --> C' is a monoidal functor between suitable symmetric clo sed categories and H is a finite commutative and cocommutative Hopf al gebra in C, we obtain, generalizing results of S. Caeneppel and M. Bea ttie, two exact sequences involving the Picard, Galois and Brauer grou ps defined in [21], [11]. Finally we describe the relation between thi s exact sequences.