Canonical Structure FunDiscr_map (i j : Discr I) :=
Build_Map (FunDiscr_map_law (i:=i) (j:=j)).

Lemma FunDiscr_id_law : Fid_law FunDiscr_map.
Canonical Structure FunDiscr :=
Build_Functor FunDiscr_comp_law FunDiscr_id_law.