  We introduce the space of parameters for the metaplectic Langlands theory as
*factorization gerbes* on the affine Grassmannian, and develop metaplectic
Langlands duality in the incarnation of the metaplectic geometric Satake
functor. We formulate a conjecture in the context of the global metaplectic
Langlands theory, which is a metaplectic version of the "vanishing theorem" of
ref. Ga5 (Theorem 4.5.2 in loc. cit.)
