Section teta_tau_def.
Variable dxc : POb (Dual D) C.
Definition Teta_arrow (f : F (OB_l dxc) --> Ob_r dxc) :=
A_eta ad (OB_l dxc) o FMor G f.
Canonical Structure Teta_tau := Build_Map Teta_arrow_map_law.
End teta_tau_def.

Lemma Teta_tau_NT_law : NT_law (F:=FunSET2_r F) (G:=FunSET2_l G) Teta_tau.