Skip to content

Commit

Permalink
refactor: deprecate duplicated RespectsIso theorem (#11115)
Browse files Browse the repository at this point in the history
Deprecates `RespectsIso.ofRestrict_morphismRestrict_iff_of_isAffine` in favor of the older `RespectsIso.basicOpen_iff_localization`, and removes a local notation that is only used in the removed proof.
  • Loading branch information
dwrensha committed Mar 2, 2024
1 parent fb2570a commit cddd40b
Showing 1 changed file with 3 additions and 20 deletions.
23 changes: 3 additions & 20 deletions Mathlib/AlgebraicGeometry/Morphisms/RingHomProperties.lean
Expand Up @@ -79,25 +79,8 @@ theorem RespectsIso.basicOpen_iff_localization (hP : RespectsIso @P) {X Y : Sche
rw [← hP.is_localization_away_iff]
#align ring_hom.respects_iso.basic_open_iff_localization RingHom.RespectsIso.basicOpen_iff_localization

local notation3 "Γ(" X:10 ")" => (Prefunctor.obj (Functor.toPrefunctor Scheme.Γ) (Opposite.op X))

theorem RespectsIso.ofRestrict_morphismRestrict_iff_of_isAffine (hP : RingHom.RespectsIso @P)
{X Y : Scheme} [IsAffine X] [IsAffine Y] (f : X ⟶ Y) (r : Y.presheaf.obj (Opposite.op ⊤)) :
P (Scheme.Γ.map (f ∣_ Y.basicOpen r).op) ↔
P (Localization.awayMap (Scheme.Γ.map f.op) r) := by
have : IsLocalization.Away (R := ↑Γ(X)) (Scheme.Γ.map f.op r) ↑Γ(X ∣_ᵤ f⁻¹ᵁ Y.basicOpen r) := by
rw [Scheme.preimage_basicOpen]
show IsLocalization.Away (R := ↑Γ(X)) (Scheme.Γ.map f.op r)
↑Γ(X ∣_ᵤ X.basicOpen (Scheme.Γ.map f.op r))
infer_instance
rw [hP.is_localization_away_iff ↑Γ(Y ∣_ᵤ Scheme.basicOpen Y r) ↑Γ(X ∣_ᵤ f⁻¹ᵁ Scheme.basicOpen Y r)
(Scheme.Γ.map f.op) r, iff_iff_eq]
congr 1
apply IsLocalization.ringHom_ext (R := ↑Γ(Y)) (Submonoid.powers r) _
rw [IsLocalization.Away.map, IsLocalization.map_comp, RingHom.algebraMap_toAlgebra,
RingHom.algebraMap_toAlgebra]
show Scheme.Γ.map _ ≫ Scheme.Γ.map _ = Scheme.Γ.map _ ≫ Scheme.Γ.map _
simp_rw [← Functor.map_comp, ← op_comp, morphismRestrict_ι]
@[deprecated] alias RespectsIso.ofRestrict_morphismRestrict_iff_of_isAffine :=
RespectsIso.basicOpen_iff_localization

theorem RespectsIso.ofRestrict_morphismRestrict_iff (hP : RingHom.RespectsIso @P) {X Y : Scheme}
[IsAffine Y] (f : X ⟶ Y) (r : Y.presheaf.obj (Opposite.op ⊤)) (U : Opens X.carrier)
Expand All @@ -109,7 +92,7 @@ theorem RespectsIso.ofRestrict_morphismRestrict_iff (hP : RingHom.RespectsIso @P
refine (hP.cancel_right_isIso _
(Scheme.Γ.mapIso (Scheme.restrictRestrictComm _ _ _).op).inv).symm.trans ?_
haveI : IsAffine _ := hU
rw [← hP.ofRestrict_morphismRestrict_iff_of_isAffine, iff_iff_eq]
rw [← hP.basicOpen_iff_localization, iff_iff_eq]
congr 1
simp only [Functor.mapIso_inv, Iso.op_inv, ← Functor.map_comp, ← op_comp, morphismRestrict_comp]
rw [← Category.assoc]
Expand Down

0 comments on commit cddd40b

Please sign in to comment.