Definition nattrans_arrow_mor_assoc {C:category} {c' c:C} {X X':[C^op,HSET]} (g:c'-->c) (x:c⇒X) (p:X-->X') : p ⟳ (x ⟲ g) = (p ⟳ x) ⟲ g := eqtohomot (nat_trans_ax p _ _ g) x.
Require Import UniMath.MoreFoundations.Tactics.