English
Intermediate stage giving an isomorphism between F.obj (op s) and OverArrows (yonedaCollectionPresheafToA F) s.hom.
Русский
Промежуточная стадия, дающая изоморфизм между F.obj (op s) и OverArrows (yonedaCollectionPresheafToA F) s.hom.
LaTeX
$$$$ F.obj (op\,s) \cong OverArrows\ (yonedaCollectionPresheafToA\ F)\ s.hom $$$$
Lean4
/-- Backward direction of the counit. -/
def counitBackward (F : (CostructuredArrow yoneda A)ᵒᵖ ⥤ Type v) (s : CostructuredArrow yoneda A) :
OverArrows (yonedaCollectionPresheafToA F) s.hom → F.obj (op s) := fun p =>
F.map (eqToHom (by simp [← CostructuredArrow.eq_mk])) p.val.snd