Section compnt.
Variables (F G H : Functor C D) (T : NT F G) (T' : NT G H).
Definition Comp_tau (a : C) := T a o T' a.
Canonical Structure CompV_NT : NT_setoid F H := Comp_tau_nt_law.
End compnt.

Lemma CompV_NT_congr : Congr_law'' CompV_NT.