Definition slice_unit : functor_identity (PreShv C / P) ⟹ slice_to_PreShv ∙ PreShv_to_slice := pr1 (nat_trafo_z_iso_if_pointwise_z_iso (has_homsets_slice_precat ((PreShv C)) P) (slice_counit) slice_all_z_iso).
Require Import UniMath.Foundations.Sets. Require Import UniMath.MoreFoundations.Tactics. Require Import UniMath.CategoryTheory.Core.Categories. Require Import UniMath.CategoryTheory.Core.Isos. Require Import UniMath.CategoryTheory.Core.Functors. Require Import UniMath.CategoryTheory.Core.NaturalTransformations. Require Import UniMath.CategoryTheory.FunctorCategory. Require Import