  Topos theory has been suggested first by Isham and Butterfield, and then by
Isham and D\"oring, as an alternative mathematical structure within which to
formulate physical theories. In particular it has been used to reformulate
standard quantum mechanics in such a way that a novel type of logic is used to
represent propositions. In this paper we extend this formulation to include the
notion of a group and group transformation in such a way that we overcome the
problem of twisted presheaves. In order to implement this we need to change the
type of topos involved, so as to render the notion of continuity of the group
action meaningful.
