“…From the definition, we find that for f ∈ V G λ and t ∈ T + , we have ), and the * -action can be viewed as an 'optimal' integral normalisation of it. (iii) For GL 2 , it is easy to write down the •-action on V G,∨ λ explicitly, and one easily sees that this explicit action extends to distributions; this is done, for example, in [2,8,35]. We warn the reader, however, that this does not give the * -action of T + on distributions defined here: in particular, it does not preserve integrality (see [8, Sect.…”