English
Given a σ, φ, τ and h, a universal property guarantees that the lift is unique up to equality of objects and maps.
Русский
При задании σ, φ, τ и h существует единственная подстановка, удовлетворяющая условиям, то есть единственная конструкция lifts'а.
LaTeX
$$$\\text{If }\\Phi,\\Phi_0,\\Phi\\text{ satisfy the given compatibilities, then }\\Phi = \\mathrm{lift}\\ σ\\ φ\\ τ\\ h.$$$
Lean4
theorem lift_comp : (of σ ⋙q lift σ φ τ h) = φ :=
by
fapply Prefunctor.ext
· rintro X
simp only [Prefunctor.comp_obj]
apply Eq.symm
exact h X
· rintro X Y f
simp only [Prefunctor.comp_map]
apply eq_of_heq
iterate 2 apply (cast_heq _ _).trans
simp