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fork : Fork.{v} (leftRes F U) (rightRes F U)
Fork.ofι _ (w F U)
def
TopCat.Presheaf.SheafConditionEqualizerProducts.fork
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/EqualizerProducts.lean
[]
[]
The restriction map `F.obj U ⟶ Π F.obj (U i)` gives a cone over the equalizer diagram for the sheaf condition. The sheaf condition asserts this cone is a limit cone.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
fork_pt : (fork F U).pt = F.obj (op (iSup U))
rfl
theorem
TopCat.Presheaf.SheafConditionEqualizerProducts.fork_pt
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/EqualizerProducts.lean
[]
[ "iSup" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
fork_ι : (fork F U).ι = res F U
rfl
theorem
TopCat.Presheaf.SheafConditionEqualizerProducts.fork_ι
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/EqualizerProducts.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
fork_π_app_walkingParallelPair_zero : (fork F U).π.app WalkingParallelPair.zero = res F U
rfl
theorem
TopCat.Presheaf.SheafConditionEqualizerProducts.fork_π_app_walkingParallelPair_zero
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/EqualizerProducts.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
fork_π_app_walkingParallelPair_one : (fork F U).π.app WalkingParallelPair.one = res F U ≫ leftRes F U
rfl
theorem
TopCat.Presheaf.SheafConditionEqualizerProducts.fork_π_app_walkingParallelPair_one
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/EqualizerProducts.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
piOpens.isoOfIso (α : F ≅ G) : piOpens F U ≅ piOpens.{v'} G U
Pi.mapIso fun _ => α.app _
def
TopCat.Presheaf.SheafConditionEqualizerProducts.piOpens.isoOfIso
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/EqualizerProducts.lean
[]
[]
Isomorphic presheaves have isomorphic `piOpens` for any cover `U`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
piInters.isoOfIso (α : F ≅ G) : piInters F U ≅ piInters.{v'} G U
Pi.mapIso fun _ => α.app _
def
TopCat.Presheaf.SheafConditionEqualizerProducts.piInters.isoOfIso
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/EqualizerProducts.lean
[]
[]
Isomorphic presheaves have isomorphic `piInters` for any cover `U`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
diagram.isoOfIso (α : F ≅ G) : diagram F U ≅ diagram.{v'} G U
NatIso.ofComponents (by rintro ⟨⟩ · exact piOpens.isoOfIso U α · exact piInters.isoOfIso U α) (by rintro ⟨⟩ ⟨⟩ ⟨⟩ · simp · dsimp refine Pi.hom_ext _ _ fun b ↦ ?_ simp [leftRes] · dsimp [diagram] refine Pi.hom_ext _ _ fun b ↦ ?_ simp [rightRes] ...
def
TopCat.Presheaf.SheafConditionEqualizerProducts.diagram.isoOfIso
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/EqualizerProducts.lean
[]
[]
Isomorphic presheaves have isomorphic sheaf condition diagrams.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
fork.isoOfIso (α : F ≅ G) : fork F U ≅ (Cone.postcompose (diagram.isoOfIso U α).inv).obj (fork G U)
by fapply Fork.ext · apply α.app · dsimp refine Pi.hom_ext _ _ fun b ↦ ?_ dsimp only [Fork.ι] simp [res, diagram.isoOfIso]
def
TopCat.Presheaf.SheafConditionEqualizerProducts.fork.isoOfIso
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/EqualizerProducts.lean
[]
[]
If `F G : Presheaf C X` are isomorphic presheaves, then the `fork F U`, the canonical cone of the sheaf condition diagram for `F`, is isomorphic to `fork F G` postcomposed with the corresponding isomorphism between sheaf condition diagrams.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
IsSheafEqualizerProducts (F : Presheaf.{v', v, u} C X) : Prop
∀ ⦃ι : Type v'⦄ (U : ι → Opens X), Nonempty (IsLimit (SheafConditionEqualizerProducts.fork F U))
def
TopCat.Presheaf.IsSheafEqualizerProducts
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/EqualizerProducts.lean
[]
[]
The sheaf condition for a `F : Presheaf C X` requires that the morphism `F.obj U ⟶ ∏ᶜ F.obj (U i)` (where `U` is some open set which is the union of the `U i`) is the equalizer of the two morphisms `∏ᶜ F.obj (U i) ⟶ ∏ᶜ F.obj (U i) ⊓ (U j)`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
coneEquivFunctorObj (c : Cone ((diagram U).op ⋙ F)) : Cone (SheafConditionEqualizerProducts.diagram F U)
where pt := c.pt π := { app := fun Z => WalkingParallelPair.casesOn Z (Pi.lift fun i : ι => c.π.app (op (single i))) (Pi.lift fun b : ι × ι => c.π.app (op (pair b.1 b.2))) naturality := fun Y Z f => by cases Y <;> cases Z <;> cases f · dsimp ext simp ...
def
TopCat.Presheaf.SheafConditionPairwiseIntersections.coneEquivFunctorObj
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/EqualizerProducts.lean
[]
[ "Quiver.Hom.op" ]
Implementation of `SheafConditionPairwiseIntersections.coneEquiv`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
coneEquivFunctor : Limits.Cone ((diagram U).op ⋙ F) ⥤ Limits.Cone (SheafConditionEqualizerProducts.diagram F U)
where obj c := coneEquivFunctorObj F U c map {c c'} f := { hom := f.hom w := fun j => by cases j <;> · dsimp ext simp }
def
TopCat.Presheaf.SheafConditionPairwiseIntersections.coneEquivFunctor
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/EqualizerProducts.lean
[]
[]
Implementation of `SheafConditionPairwiseIntersections.coneEquiv`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
coneEquivInverseObj (c : Limits.Cone (SheafConditionEqualizerProducts.diagram F U)) : Limits.Cone ((diagram U).op ⋙ F)
where pt := c.pt π := { app := by intro x induction x with | op x => ?_ rcases x with (⟨i⟩ | ⟨i, j⟩) · exact c.π.app WalkingParallelPair.zero ≫ Pi.π _ i · exact c.π.app WalkingParallelPair.one ≫ Pi.π _ (i, j) naturality := by intro x y f induction x ...
def
TopCat.Presheaf.SheafConditionPairwiseIntersections.coneEquivInverseObj
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/EqualizerProducts.lean
[]
[]
Implementation of `SheafConditionPairwiseIntersections.coneEquiv`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
coneEquivInverse : Limits.Cone (SheafConditionEqualizerProducts.diagram F U) ⥤ Limits.Cone ((diagram U).op ⋙ F)
where obj c := coneEquivInverseObj F U c map {c c'} f := { hom := f.hom w := by intro x induction x with | op x => ?_ rcases x with (⟨i⟩ | ⟨i, j⟩) · dsimp dsimp only [Fork.ι] rw [← f.w WalkingParallelPair.zero, Category.assoc] · dsimp r...
def
TopCat.Presheaf.SheafConditionPairwiseIntersections.coneEquivInverse
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/EqualizerProducts.lean
[]
[]
Implementation of `SheafConditionPairwiseIntersections.coneEquiv`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
coneEquivUnitIsoApp (c : Cone ((diagram U).op ⋙ F)) : (𝟭 (Cone ((diagram U).op ⋙ F))).obj c ≅ (coneEquivFunctor F U ⋙ coneEquivInverse F U).obj c
where hom := { hom := 𝟙 _ w := fun j => by induction j with | op j => ?_ rcases j with ⟨⟩ <;> · dsimp [coneEquivInverse] simp only [Limits.Fan.mk_π_app, Category.id_comp, Limits.limit.lift_π] } inv := { hom := 𝟙 _ w := fun j => by induction j with | op...
def
TopCat.Presheaf.SheafConditionPairwiseIntersections.coneEquivUnitIsoApp
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/EqualizerProducts.lean
[]
[]
Implementation of `SheafConditionPairwiseIntersections.coneEquiv`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
coneEquivUnitIso : 𝟭 (Limits.Cone ((diagram U).op ⋙ F)) ≅ coneEquivFunctor F U ⋙ coneEquivInverse F U
NatIso.ofComponents (coneEquivUnitIsoApp F U)
def
TopCat.Presheaf.SheafConditionPairwiseIntersections.coneEquivUnitIso
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/EqualizerProducts.lean
[]
[]
Implementation of `SheafConditionPairwiseIntersections.coneEquiv`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
coneEquivCounitIso : coneEquivInverse F U ⋙ coneEquivFunctor F U ≅ 𝟭 (Limits.Cone (SheafConditionEqualizerProducts.diagram F U))
NatIso.ofComponents (fun c => { hom := { hom := 𝟙 _ w := by rintro ⟨_ | _⟩ · dsimp ext simp · dsimp ext simp } inv := { hom := 𝟙 _ w := by ...
def
TopCat.Presheaf.SheafConditionPairwiseIntersections.coneEquivCounitIso
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/EqualizerProducts.lean
[]
[]
Implementation of `SheafConditionPairwiseIntersections.coneEquiv`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
coneEquiv : Limits.Cone ((diagram U).op ⋙ F) ≌ Limits.Cone (SheafConditionEqualizerProducts.diagram F U)
where functor := coneEquivFunctor F U inverse := coneEquivInverse F U unitIso := coneEquivUnitIso F U counitIso := coneEquivCounitIso F U
def
TopCat.Presheaf.SheafConditionPairwiseIntersections.coneEquiv
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/EqualizerProducts.lean
[]
[]
Cones over `diagram U ⋙ F` are the same as a cones over the usual sheaf condition equalizer diagram.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isLimitMapConeOfIsLimitSheafConditionFork (P : IsLimit (SheafConditionEqualizerProducts.fork F U)) : IsLimit (F.mapCone (cocone U).op)
IsLimit.ofIsoLimit ((IsLimit.ofConeEquiv (coneEquiv F U).symm).symm P) { hom := { hom := 𝟙 _ w := by intro x induction x with | op x => ?_ rcases x with ⟨⟩ · simp rfl · dsimp [coneEquivInverse, SheafConditionEqualizerProduc...
def
TopCat.Presheaf.SheafConditionPairwiseIntersections.isLimitMapConeOfIsLimitSheafConditionFork
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/EqualizerProducts.lean
[]
[ "symm" ]
If `SheafConditionEqualizerProducts.fork` is an equalizer, then `F.mapCone (cone U)` is a limit cone.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isLimitSheafConditionForkOfIsLimitMapCone (Q : IsLimit (F.mapCone (cocone U).op)) : IsLimit (SheafConditionEqualizerProducts.fork F U)
IsLimit.ofIsoLimit ((IsLimit.ofConeEquiv (coneEquiv F U)).symm Q) { hom := { hom := 𝟙 _ w := by rintro ⟨⟩ · simp rfl · dsimp ext dsimp [coneEquivInverse, SheafConditionEqualizerProducts.res, SheafConditi...
def
TopCat.Presheaf.SheafConditionPairwiseIntersections.isLimitSheafConditionForkOfIsLimitMapCone
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/EqualizerProducts.lean
[]
[ "symm" ]
If `F.mapCone (cone U)` is a limit cone, then `SheafConditionEqualizerProducts.fork` is an equalizer.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isSheaf_iff_isSheafEqualizerProducts (F : Presheaf C X) : F.IsSheaf ↔ F.IsSheafEqualizerProducts
(isSheaf_iff_isSheafPairwiseIntersections F).trans <| Iff.intro (fun h _ U => ⟨isLimitSheafConditionForkOfIsLimitMapCone F U (h U).some⟩) fun h _ U => ⟨isLimitMapConeOfIsLimitSheafConditionFork F U (h U).some⟩
theorem
TopCat.Presheaf.isSheaf_iff_isSheafEqualizerProducts
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/EqualizerProducts.lean
[]
[ "trans" ]
The sheaf condition in terms of an equalizer diagram is equivalent to the default sheaf condition.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
OpensLeCover : Type w
ObjectProperty.FullSubcategory fun V : Opens X ↦ ∃ i, V ≤ U i deriving Category
def
TopCat.Presheaf.SheafCondition.OpensLeCover
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/OpensLeCover.lean
[]
[]
The category of open sets contained in some element of the cover.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
index (V : OpensLeCover U) : ι
V.property.choose
def
TopCat.Presheaf.SheafCondition.OpensLeCover.index
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/OpensLeCover.lean
[]
[]
An arbitrarily chosen index such that `V ≤ U i`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
homToIndex (V : OpensLeCover U) : V.obj ⟶ U (index V)
V.property.choose_spec.hom
def
TopCat.Presheaf.SheafCondition.OpensLeCover.homToIndex
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/OpensLeCover.lean
[]
[]
The morphism from `V` to `U i` for some `i`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
opensLeCoverCocone : Cocone (ObjectProperty.ι _ : OpensLeCover U ⥤ Opens X)
where pt := iSup U ι := { app := fun V : OpensLeCover U => V.homToIndex ≫ Opens.leSupr U _ }
def
TopCat.Presheaf.SheafCondition.opensLeCoverCocone
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/OpensLeCover.lean
[]
[ "iSup" ]
`iSup U` as a cocone over the opens sets contained in some element of the cover. (In fact this is a colimit cocone.)
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
IsSheafOpensLeCover : Prop
∀ ⦃ι : Type w⦄ (U : ι → Opens X), Nonempty (IsLimit (F.mapCone (opensLeCoverCocone U).op))
def
TopCat.Presheaf.IsSheafOpensLeCover
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/OpensLeCover.lean
[]
[]
An equivalent formulation of the sheaf condition (which we prove equivalent to the usual one below as `isSheaf_iff_isSheafOpensLeCover`). A presheaf is a sheaf if `F` sends the cone `(opensLeCoverCocone U).op` to a limit cone. (Recall `opensLeCoverCocone U`, has cone point `iSup U`, mapping down to any `V` which is co...
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
generateEquivalenceOpensLe_functor' : (ObjectProperty.FullSubcategory fun f : Over Y => (Sieve.generate (presieveOfCoveringAux U Y)).arrows f.hom) ⥤ OpensLeCover U
where obj f := ⟨f.1.left, let ⟨_, h, _, ⟨i, hY⟩, _⟩ := f.2 ⟨i, hY ▸ h.le⟩⟩ map g := ObjectProperty.homMk g.hom.left
def
TopCat.Presheaf.generateEquivalenceOpensLe_functor'
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/OpensLeCover.lean
[]
[]
Given a family of opens `U` and an open `Y` equal to the union of opens in `U`, we may take the presieve on `Y` associated to `U` and the sieve generated by it, and form the full subcategory (subposet) of opens contained in `Y` (`over Y`) consisting of arrows in the sieve. This full subcategory is equivalent to `OpensL...
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
generateEquivalenceOpensLe_inverse' (hY : Y = iSup U) : OpensLeCover U ⥤ (ObjectProperty.FullSubcategory fun f : Over Y => (Sieve.generate (presieveOfCoveringAux U Y)).arrows f.hom)
where obj := fun V => ⟨⟨V.obj, ⟨⟨⟩⟩, homOfLE <| hY ▸ (V.2.choose_spec.trans (le_iSup U (V.2.choose)))⟩, ⟨U V.2.choose, V.2.choose_spec.hom, homOfLE <| hY ▸ le_iSup U V.2.choose, ⟨V.2.choose, rfl⟩, rfl⟩⟩ map g := ObjectProperty.homMk (Over.homMk g.hom)
def
TopCat.Presheaf.generateEquivalenceOpensLe_inverse'
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/OpensLeCover.lean
[]
[ "iSup", "le_iSup" ]
Given a family of opens `U` and an open `Y` equal to the union of opens in `U`, we may take the presieve on `Y` associated to `U` and the sieve generated by it, and form the full subcategory (subposet) of opens contained in `Y` (`over Y`) consisting of arrows in the sieve. This full subcategory is equivalent to `OpensL...
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
generateEquivalenceOpensLe (hY : Y = iSup U) : (ObjectProperty.FullSubcategory fun f : Over Y => (Sieve.generate (presieveOfCoveringAux U Y)).arrows f.hom) ≌ OpensLeCover U
where functor := generateEquivalenceOpensLe_functor' _ inverse := generateEquivalenceOpensLe_inverse' _ hY unitIso := eqToIso <| CategoryTheory.Functor.ext (by cat_disch) counitIso := eqToIso <| CategoryTheory.Functor.ext (by cat_disch)
def
TopCat.Presheaf.generateEquivalenceOpensLe
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/OpensLeCover.lean
[]
[ "CategoryTheory.Functor.ext", "iSup" ]
Given a family of opens `U` and an open `Y` equal to the union of opens in `U`, we may take the presieve on `Y` associated to `U` and the sieve generated by it, and form the full subcategory (subposet) of opens contained in `Y` (`over Y`) consisting of arrows in the sieve. This full subcategory is equivalent to `OpensL...
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
whiskerIsoMapGenerateCocone (hY : Y = iSup U) : (F.mapCone (opensLeCoverCocone U).op).whisker (generateEquivalenceOpensLe U hY).op.functor ≅ F.mapCone (Sieve.generate (presieveOfCoveringAux U Y)).arrows.cocone.op
where hom := { hom := F.map (eqToHom (congr_arg op hY.symm)) w := fun j => by dsimp rw [← F.map_comp] congr 1 } inv := { hom := F.map (eqToHom (congr_arg op hY)) w := fun j => by dsimp rw [← F.map_comp] congr 1 } hom_inv_id := by ext simp...
def
TopCat.Presheaf.whiskerIsoMapGenerateCocone
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/OpensLeCover.lean
[]
[ "iSup" ]
Given a family of opens `opensLeCoverCocone U` is essentially the natural cocone associated to the sieve generated by the presieve associated to `U` with indexing category changed using the above equivalence.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isLimitOpensLeEquivGenerate₁ (hY : Y = iSup U) : IsLimit (F.mapCone (opensLeCoverCocone U).op) ≃ IsLimit (F.mapCone (Sieve.generate (presieveOfCoveringAux U Y)).arrows.cocone.op)
(IsLimit.whiskerEquivalenceEquiv (generateEquivalenceOpensLe U hY).op).trans (IsLimit.equivIsoLimit (whiskerIsoMapGenerateCocone F U hY))
def
TopCat.Presheaf.isLimitOpensLeEquivGenerate₁
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/OpensLeCover.lean
[]
[ "iSup", "trans" ]
Given a presheaf `F` on the topological space `X` and a family of opens `U` of `X`, the natural cone associated to `F` and `U` used in the definition of `F.IsSheafOpensLeCover` is a limit cone iff the natural cone associated to `F` and the sieve generated by the presieve associated to `U` is a limit cone.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isLimitOpensLeEquivGenerate₂ (R : Presieve Y) (hR : Sieve.generate R ∈ Opens.grothendieckTopology X Y) : IsLimit (F.mapCone (opensLeCoverCocone (coveringOfPresieve Y R)).op) ≃ IsLimit (F.mapCone (Sieve.generate R).arrows.cocone.op)
by convert! isLimitOpensLeEquivGenerate₁ F (coveringOfPresieve Y R) (coveringOfPresieve.iSup_eq_of_mem_grothendieck Y R hR).symm using 1 rw [covering_presieve_eq_self R]
def
TopCat.Presheaf.isLimitOpensLeEquivGenerate₂
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/OpensLeCover.lean
[]
[ "Opens.grothendieckTopology", "symm" ]
Given a presheaf `F` on the topological space `X` and a presieve `R` whose generated sieve is covering for the associated Grothendieck topology (equivalently, the presieve is covering for the associated pretopology), the natural cone associated to `F` and the family of opens associated to `R` is a limit cone iff the na...
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
IsSheaf.isSheafOpensLeCover (h : F.IsSheaf) : Nonempty (IsLimit (F.mapCone (opensLeCoverCocone U).op))
by rw [(isLimitOpensLeEquivGenerate₁ F U rfl).nonempty_congr] apply (Presheaf.isSheaf_iff_isLimit _ _).mp h apply presieveOfCovering.mem_grothendieckTopology
theorem
TopCat.Presheaf.IsSheaf.isSheafOpensLeCover
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/OpensLeCover.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isSheaf_iff_isSheafOpensLeCover : F.IsSheaf ↔ F.IsSheafOpensLeCover
by refine ⟨fun h _ ↦ h.isSheafOpensLeCover, fun h ↦ (Presheaf.isSheaf_iff_isLimit _ _).mpr fun Y S ↦ ?_⟩ rw [← Sieve.generate_sieve S] intro hS rw [← (isLimitOpensLeEquivGenerate₂ F S.1 hS).nonempty_congr] apply h
theorem
TopCat.Presheaf.isSheaf_iff_isSheafOpensLeCover
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/OpensLeCover.lean
[]
[]
A presheaf `(opens X)ᵒᵖ ⥤ C` on a topological space `X` is a sheaf on the site `opens X` iff it satisfies the `IsSheafOpensLeCover` sheaf condition. The latter is not the official definition of sheaves on spaces, but has the advantage that it does not require `has_products C`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
IsSheafPairwiseIntersections (F : Presheaf C X) : Prop
∀ ⦃ι : Type w⦄ (U : ι → Opens X), Nonempty (IsLimit (F.mapCone (Pairwise.cocone U).op))
def
TopCat.Presheaf.IsSheafPairwiseIntersections
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/PairwiseIntersections.lean
[]
[]
An alternative formulation of the sheaf condition (which we prove equivalent to the usual one below as `isSheaf_iff_isSheafPairwiseIntersections`). A presheaf is a sheaf if `F` sends the cone `(Pairwise.cocone U).op` to a limit cone. (Recall `Pairwise.cocone U` has cone point `iSup U`, mapping down to the `U i` and th...
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
IsSheafPreservesLimitPairwiseIntersections (F : Presheaf C X) : Prop
∀ ⦃ι : Type w⦄ (U : ι → Opens X), PreservesLimit (Pairwise.diagram U).op F
def
TopCat.Presheaf.IsSheafPreservesLimitPairwiseIntersections
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/PairwiseIntersections.lean
[]
[]
An alternative formulation of the sheaf condition (which we prove equivalent to the usual one below as `isSheaf_iff_isSheafPreservesLimitPairwiseIntersections`). A presheaf is a sheaf if `F` preserves the limit of `Pairwise.diagram U`. (Recall `Pairwise.diagram U` is the diagram consisting of the pairwise intersection...
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
pairwiseToOpensLeCoverObj : Pairwise ι → OpensLeCover U
| single i => ⟨U i, ⟨i, le_rfl⟩⟩ | Pairwise.pair i j => ⟨U i ⊓ U j, ⟨i, inf_le_left⟩⟩
def
TopCat.Presheaf.SheafCondition.pairwiseToOpensLeCoverObj
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/PairwiseIntersections.lean
[]
[ "Pairwise" ]
Implementation detail: the object level of `pairwiseToOpensLeCover : Pairwise ι ⥤ OpensLeCover U`
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
pairwiseToOpensLeCoverMap : ∀ {V W : Pairwise ι}, (V ⟶ W) → (pairwiseToOpensLeCoverObj U V ⟶ pairwiseToOpensLeCoverObj U W)
| _, _, id_single _ => 𝟙 _ | _, _, id_pair _ _ => 𝟙 _ | _, _, left _ _ => ObjectProperty.homMk (homOfLE inf_le_left) | _, _, right _ _ => ObjectProperty.homMk (homOfLE inf_le_right)
def
TopCat.Presheaf.SheafCondition.pairwiseToOpensLeCoverMap
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/PairwiseIntersections.lean
[]
[ "Pairwise" ]
Implementation detail: the morphism level of `pairwiseToOpensLeCover : Pairwise ι ⥤ OpensLeCover U`
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
pairwiseToOpensLeCover : Pairwise ι ⥤ OpensLeCover U
where obj := pairwiseToOpensLeCoverObj U map {_ _} i := pairwiseToOpensLeCoverMap U i
def
TopCat.Presheaf.SheafCondition.pairwiseToOpensLeCover
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/PairwiseIntersections.lean
[]
[ "Pairwise" ]
The category of single and double intersections of the `U i` maps into the category of open sets below some `U i`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
pairwiseDiagramIso : Pairwise.diagram U ≅ pairwiseToOpensLeCover U ⋙ ObjectProperty.ι _
where hom := { app := by rintro (i | ⟨i, j⟩) <;> exact 𝟙 _ } inv := { app := by rintro (i | ⟨i, j⟩) <;> exact 𝟙 _ }
def
TopCat.Presheaf.SheafCondition.pairwiseDiagramIso
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/PairwiseIntersections.lean
[]
[]
The diagram in `Opens X` indexed by pairwise intersections from `U` is isomorphic (in fact, equal) to the diagram factored through `OpensLeCover U`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
pairwiseCoconeIso : (Pairwise.cocone U).op ≅ (Cone.postcomposeEquivalence (NatIso.op (pairwiseDiagramIso U :) :)).functor.obj ((opensLeCoverCocone U).op.whisker (pairwiseToOpensLeCover U).op)
Cone.ext (Iso.refl _) (by cat_disch)
def
TopCat.Presheaf.SheafCondition.pairwiseCoconeIso
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/PairwiseIntersections.lean
[]
[]
The cocone `Pairwise.cocone U` with cocone point `iSup U` over `Pairwise.diagram U` is isomorphic to the cocone `opensLeCoverCocone U` (with the same cocone point) after appropriate whiskering and postcomposition.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isLimitOpensLeCoverEquivPairwise : IsLimit (F.mapCone (opensLeCoverCocone U).op) ≃ IsLimit (F.mapCone (Pairwise.cocone U).op)
calc IsLimit (F.mapCone (opensLeCoverCocone U).op) ≃ IsLimit ((F.mapCone (opensLeCoverCocone U).op).whisker (pairwiseToOpensLeCover U).op) := (Functor.Initial.isLimitWhiskerEquiv (pairwiseToOpensLeCover U).op _).symm _ ≃ IsLimit (F.mapCone ((opensLeCoverCocone U).op.whisker (pairwiseToOpensLeCover...
def
TopCat.Presheaf.isLimitOpensLeCoverEquivPairwise
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/PairwiseIntersections.lean
[]
[ "symm" ]
The diagram over all `{ V : Opens X // ∃ i, V ≤ U i }` is a limit iff the diagram over `U i` and `U i ⊓ U j` is a limit.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isSheafOpensLeCover_iff_isSheafPairwiseIntersections : F.IsSheafOpensLeCover ↔ F.IsSheafPairwiseIntersections
forall₂_congr fun _ U ↦ (F.isLimitOpensLeCoverEquivPairwise U).nonempty_congr
theorem
TopCat.Presheaf.isSheafOpensLeCover_iff_isSheafPairwiseIntersections
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/PairwiseIntersections.lean
[]
[]
The sheaf condition in terms of a limit diagram over all `{ V : Opens X // ∃ i, V ≤ U i }` is equivalent to the reformulation in terms of a limit diagram over `U i` and `U i ⊓ U j`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
IsSheaf.isSheafPairwiseIntersections (h : F.IsSheaf) : Nonempty (IsLimit (F.mapCone (Pairwise.cocone U).op))
(h.isSheafOpensLeCover U).map (F.isLimitOpensLeCoverEquivPairwise _)
theorem
TopCat.Presheaf.IsSheaf.isSheafPairwiseIntersections
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/PairwiseIntersections.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isSheaf_iff_isSheafPairwiseIntersections : F.IsSheaf ↔ F.IsSheafPairwiseIntersections
by rw [isSheaf_iff_isSheafOpensLeCover, isSheafOpensLeCover_iff_isSheafPairwiseIntersections]
theorem
TopCat.Presheaf.isSheaf_iff_isSheafPairwiseIntersections
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/PairwiseIntersections.lean
[]
[]
The sheaf condition in terms of an equalizer diagram is equivalent to the reformulation in terms of a limit diagram over `U i` and `U i ⊓ U j`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
IsSheaf.isSheafPreservesLimitPairwiseIntersections (h : F.IsSheaf) : PreservesLimit (Pairwise.diagram U).op F
preservesLimit_of_preserves_limit_cone (Pairwise.coconeIsColimit U).op (h.isSheafPairwiseIntersections U).some
theorem
TopCat.Presheaf.IsSheaf.isSheafPreservesLimitPairwiseIntersections
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/PairwiseIntersections.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isSheaf_iff_isSheafPreservesLimitPairwiseIntersections : F.IsSheaf ↔ F.IsSheafPreservesLimitPairwiseIntersections
by refine ⟨fun h U ↦ h.isSheafPreservesLimitPairwiseIntersections, fun h ↦ F.isSheaf_iff_isSheafPairwiseIntersections.mpr fun ι U ↦ ?_⟩ haveI := h U exact ⟨isLimitOfPreserves _ (Pairwise.coconeIsColimit U).op⟩
theorem
TopCat.Presheaf.isSheaf_iff_isSheafPreservesLimitPairwiseIntersections
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/PairwiseIntersections.lean
[]
[]
The sheaf condition in terms of an equalizer diagram is equivalent to the reformulation in terms of the presheaf preserving the limit of the diagram consisting of the `U i` and `U i ⊓ U j`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
interUnionPullbackCone : PullbackCone (F.1.map (homOfLE inf_le_left : U ⊓ V ⟶ _).op) (F.1.map (homOfLE inf_le_right).op)
PullbackCone.mk (F.1.map (homOfLE le_sup_left).op) (F.1.map (homOfLE le_sup_right).op) <| by rw [← F.1.map_comp, ← F.1.map_comp] congr 1
def
TopCat.Sheaf.interUnionPullbackCone
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/PairwiseIntersections.lean
[]
[ "le_sup_left", "le_sup_right" ]
For a sheaf `F`, `F(U ⊔ V)` is the pullback of `F(U) ⟶ F(U ⊓ V)` and `F(V) ⟶ F(U ⊓ V)`. This is the pullback cone.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
interUnionPullbackCone_pt : (interUnionPullbackCone F U V).pt = F.1.obj (op <| U ⊔ V)
rfl
theorem
TopCat.Sheaf.interUnionPullbackCone_pt
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/PairwiseIntersections.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
interUnionPullbackCone_fst : (interUnionPullbackCone F U V).fst = F.1.map (homOfLE le_sup_left).op
rfl
theorem
TopCat.Sheaf.interUnionPullbackCone_fst
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/PairwiseIntersections.lean
[]
[ "le_sup_left" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
interUnionPullbackCone_snd : (interUnionPullbackCone F U V).snd = F.1.map (homOfLE le_sup_right).op
rfl
theorem
TopCat.Sheaf.interUnionPullbackCone_snd
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/PairwiseIntersections.lean
[]
[ "le_sup_right" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
interUnionPullbackConeLift : s.pt ⟶ F.1.obj (op (U ⊔ V))
by let ι : ULift.{w} WalkingPair → Opens X := fun j => WalkingPair.casesOn j.down U V have hι : U ⊔ V = iSup ι := by ext rw [Opens.coe_iSup, Set.mem_iUnion] constructor · rintro (h | h) exacts [⟨⟨WalkingPair.left⟩, h⟩, ⟨⟨WalkingPair.right⟩, h⟩] · rintro ⟨⟨_ | _⟩, h⟩ exacts [Or.inl h,...
def
TopCat.Sheaf.interUnionPullbackConeLift
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/PairwiseIntersections.lean
[]
[ "Set.mem_iUnion", "iSup" ]
(Implementation). Every cone over `F(U) ⟶ F(U ⊓ V)` and `F(V) ⟶ F(U ⊓ V)` factors through `F(U ⊔ V)`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
interUnionPullbackConeLift_left : interUnionPullbackConeLift F U V s ≫ F.1.map (homOfLE le_sup_left).op = s.fst
by rw [interUnionPullbackConeLift, Category.assoc, ← F.1.map_comp] exact (F.presheaf.isSheaf_iff_isSheafPairwiseIntersections.mp F.2 _).some.fac _ <| op <| Pairwise.single <| ULift.up WalkingPair.left
theorem
TopCat.Sheaf.interUnionPullbackConeLift_left
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/PairwiseIntersections.lean
[]
[ "le_sup_left" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
interUnionPullbackConeLift_right : interUnionPullbackConeLift F U V s ≫ F.1.map (homOfLE le_sup_right).op = s.snd
by rw [interUnionPullbackConeLift, Category.assoc, ← F.1.map_comp] exact (F.presheaf.isSheaf_iff_isSheafPairwiseIntersections.mp F.2 _).some.fac _ <| op <| Pairwise.single <| ULift.up WalkingPair.right
theorem
TopCat.Sheaf.interUnionPullbackConeLift_right
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/PairwiseIntersections.lean
[]
[ "le_sup_right" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isLimitPullbackCone : IsLimit (interUnionPullbackCone F U V)
by let ι : ULift.{w} WalkingPair → Opens X := fun ⟨j⟩ => WalkingPair.casesOn j U V have hι : U ⊔ V = iSup ι := by ext rw [Opens.coe_iSup, Set.mem_iUnion] constructor · rintro (h | h) exacts [⟨⟨WalkingPair.left⟩, h⟩, ⟨⟨WalkingPair.right⟩, h⟩] · rintro ⟨⟨_ | _⟩, h⟩ exacts [Or.inl h, Or...
def
TopCat.Sheaf.isLimitPullbackCone
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/PairwiseIntersections.lean
[]
[ "Set.mem_iUnion", "iSup" ]
For a sheaf `F`, `F(U ⊔ V)` is the pullback of `F(U) ⟶ F(U ⊓ V)` and `F(V) ⟶ F(U ⊓ V)`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isProductOfDisjoint (h : U ⊓ V = ⊥) : IsLimit (BinaryFan.mk (F.1.map (homOfLE le_sup_left : _ ⟶ U ⊔ V).op) (F.1.map (homOfLE le_sup_right : _ ⟶ U ⊔ V).op))
isProductOfIsTerminalIsPullback _ _ _ _ (F.isTerminalOfEqEmpty h) (isLimitPullbackCone F U V)
def
TopCat.Sheaf.isProductOfDisjoint
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/PairwiseIntersections.lean
[]
[ "isProductOfIsTerminalIsPullback", "le_sup_left", "le_sup_right" ]
If `U, V` are disjoint, then `F(U ⊔ V) = F(U) × F(V)`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
coveringOfPresieve (U : Opens X) (R : Presieve U) : (Σ V, { f : V ⟶ U // R f }) → Opens X
fun f => f.1
def
TopCat.Presheaf.coveringOfPresieve
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/Sites.lean
[]
[]
Given a presieve `R` on `U`, we obtain a covering family of open sets in `X`, by taking as index type the type of dependent pairs `(V, f)`, where `f : V ⟶ U` is in `R`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
coveringOfPresieve_apply (U : Opens X) (R : Presieve U) (f : Σ V, { f : V ⟶ U // R f }) : coveringOfPresieve U R f = f.1
rfl
theorem
TopCat.Presheaf.coveringOfPresieve_apply
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/Sites.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
iSup_eq_of_mem_grothendieck (hR : Sieve.generate R ∈ Opens.grothendieckTopology X U) : iSup (coveringOfPresieve U R) = U
by apply le_antisymm · refine iSup_le ?_ intro f exact f.2.1.le intro x hxU rw [Opens.mem_iSup] obtain ⟨V, iVU, ⟨W, iVW, iWU, hiWU, -⟩, hxV⟩ := hR x hxU exact ⟨⟨W, ⟨iWU, hiWU⟩⟩, iVW.le hxV⟩
theorem
TopCat.Presheaf.coveringOfPresieve.iSup_eq_of_mem_grothendieck
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/Sites.lean
[]
[ "Opens.grothendieckTopology", "iSup", "iSup_le", "le_antisymm" ]
If `R` is a presieve in the Grothendieck topology on `Opens X`, the covering family associated to `R` really is _covering_, i.e. the union of all open sets equals `U`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
presieveOfCoveringAux {ι : Type v} (U : ι → Opens X) (Y : Opens X) : Presieve Y
fun V _ => ∃ i, V = U i
def
TopCat.Presheaf.presieveOfCoveringAux
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/Sites.lean
[]
[]
Given a family of opens `U : ι → Opens X` and any open `Y : Opens X`, we obtain a presieve on `Y` by declaring that a morphism `f : V ⟶ Y` is a member of the presieve if and only if there exists an index `i : ι` such that `V = U i`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
presieveOfCovering {ι : Type v} (U : ι → Opens X) : Presieve (iSup U)
presieveOfCoveringAux U (iSup U)
def
TopCat.Presheaf.presieveOfCovering
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/Sites.lean
[]
[ "iSup" ]
Take `Y` to be `iSup U` and obtain a presieve over `iSup U`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
covering_presieve_eq_self {Y : Opens X} (R : Presieve Y) : presieveOfCoveringAux (coveringOfPresieve Y R) Y = R
by funext Z ext f exact ⟨fun ⟨⟨_, f', h⟩, rfl⟩ => by rwa [Subsingleton.elim f f'], fun h => ⟨⟨Z, f, h⟩, rfl⟩⟩
theorem
TopCat.Presheaf.covering_presieve_eq_self
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/Sites.lean
[]
[]
Given a presieve `R` on `Y`, if we take its associated family of opens via `coveringOfPresieve` (which may not cover `Y` if `R` is not covering), and take the presieve on `Y` associated to the family of opens via `presieveOfCoveringAux`, then we get back the original presieve `R`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
mem_grothendieckTopology : Sieve.generate (presieveOfCovering U) ∈ Opens.grothendieckTopology X (iSup U)
by intro x hx obtain ⟨i, hxi⟩ := Opens.mem_iSup.mp hx exact ⟨U i, Opens.leSupr U i, ⟨U i, 𝟙 _, Opens.leSupr U i, ⟨i, rfl⟩, Category.id_comp _⟩, hxi⟩
theorem
TopCat.Presheaf.presieveOfCovering.mem_grothendieckTopology
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/Sites.lean
[]
[ "Opens.grothendieckTopology", "iSup" ]
The sieve generated by `presieveOfCovering U` is a member of the Grothendieck topology.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
homOfIndex (i : ι) : Σ V, { f : V ⟶ iSup U // presieveOfCovering U f }
⟨U i, Opens.leSupr U i, i, rfl⟩
def
TopCat.Presheaf.presieveOfCovering.homOfIndex
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/Sites.lean
[]
[ "iSup" ]
An index `i : ι` can be turned into a dependent pair `(V, f)`, where `V` is an open set and `f : V ⟶ iSup U` is a member of `presieveOfCovering U f`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
indexOfHom (f : Σ V, { f : V ⟶ iSup U // presieveOfCovering U f }) : ι
f.2.2.choose
def
TopCat.Presheaf.presieveOfCovering.indexOfHom
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/Sites.lean
[]
[ "iSup" ]
By using the axiom of choice, a dependent pair `(V, f)` where `f : V ⟶ iSup U` is a member of `presieveOfCovering U f` can be turned into an index `i : ι`, such that `V = U i`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
indexOfHom_spec (f : Σ V, { f : V ⟶ iSup U // presieveOfCovering U f }) : f.1 = U (indexOfHom U f)
f.2.2.choose_spec
theorem
TopCat.Presheaf.presieveOfCovering.indexOfHom_spec
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/Sites.lean
[]
[ "iSup" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
coverDense_iff_isBasis [Category* ι] (B : ι ⥤ Opens X) : B.IsCoverDense (Opens.grothendieckTopology X) ↔ Opens.IsBasis (Set.range B.obj)
by rw [Opens.isBasis_iff_nbhd] constructor · intro hd U x hx; rcases hd.1 U x hx with ⟨V, f, ⟨i, f₁, f₂, _⟩, hV⟩ exact ⟨B.obj i, ⟨i, rfl⟩, f₁.le hV, f₂.le⟩ intro hb; constructor; intro U x hx; rcases hb hx with ⟨_, ⟨i, rfl⟩, hx, hi⟩ exact ⟨B.obj i, ⟨⟨hi⟩⟩, ⟨⟨i, 𝟙 _, ⟨⟨hi⟩⟩, rfl⟩⟩, hx⟩
theorem
TopCat.Opens.coverDense_iff_isBasis
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/Sites.lean
[]
[ "Opens.grothendieckTopology", "Set.range", "f₁", "f₂" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
coverDense_inducedFunctor {B : ι → Opens X} (h : Opens.IsBasis (Set.range B)) : (inducedFunctor B).IsCoverDense (Opens.grothendieckTopology X)
(coverDense_iff_isBasis _).2 h
theorem
TopCat.Opens.coverDense_inducedFunctor
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/Sites.lean
[]
[ "Opens.grothendieckTopology", "Set.range" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Topology.IsOpenEmbedding.compatiblePreserving (hf : IsOpenEmbedding f) : CompatiblePreserving (Opens.grothendieckTopology Y) hf.functor
by haveI : Mono f := (TopCat.mono_iff_injective f).mpr hf.injective apply compatiblePreservingOfDownwardsClosed intro U V i refine ⟨(Opens.map f).obj V, eqToIso <| Opens.ext <| Set.image_preimage_eq_of_subset fun x h ↦ ?_⟩ obtain ⟨_, _, rfl⟩ := i.le h exact ⟨_, rfl⟩
theorem
Topology.IsOpenEmbedding.compatiblePreserving
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/Sites.lean
[]
[ "Opens.grothendieckTopology", "Set.image_preimage_eq_of_subset", "TopCat.mono_iff_injective" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
IsOpenMap.coverPreserving (hf : IsOpenMap f) : CoverPreserving (Opens.grothendieckTopology X) (Opens.grothendieckTopology Y) hf.functor
by constructor rintro U S hU _ ⟨x, hx, rfl⟩ obtain ⟨V, i, hV, hxV⟩ := hU x hx exact ⟨_, hf.functor.map i, ⟨_, i, 𝟙 _, hV, rfl⟩, Set.mem_image_of_mem f hxV⟩
theorem
IsOpenMap.coverPreserving
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/Sites.lean
[]
[ "IsOpenMap", "Opens.grothendieckTopology", "Set.mem_image_of_mem" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Topology.IsOpenEmbedding.functor_isContinuous (h : IsOpenEmbedding f) : h.functor.IsContinuous (Opens.grothendieckTopology X) (Opens.grothendieckTopology Y)
by apply Functor.isContinuous_of_coverPreserving · exact h.compatiblePreserving · exact h.isOpenMap.coverPreserving
lemma
Topology.IsOpenEmbedding.functor_isContinuous
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/Sites.lean
[]
[ "Opens.grothendieckTopology" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
TopCat.Presheaf.isSheaf_of_isOpenEmbedding (h : IsOpenEmbedding f) (hF : F.IsSheaf) : IsSheaf (h.functor.op ⋙ F)
by have := h.functor_isContinuous exact Functor.op_comp_isSheaf _ _ _ ⟨_, hF⟩
theorem
TopCat.Presheaf.isSheaf_of_isOpenEmbedding
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/Sites.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
compatiblePreserving_opens_map : CompatiblePreserving (Opens.grothendieckTopology X) (Opens.map f)
compatiblePreservingOfFlat _ _
theorem
compatiblePreserving_opens_map
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/Sites.lean
[]
[ "Opens.grothendieckTopology" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
coverPreserving_opens_map : CoverPreserving (Opens.grothendieckTopology Y) (Opens.grothendieckTopology X) (Opens.map f)
by constructor intro U S hS x hx obtain ⟨V, i, hi, hxV⟩ := hS (f x) hx exact ⟨_, (Opens.map f).map i, ⟨_, _, 𝟙 _, hi, Subsingleton.elim _ _⟩, hxV⟩
theorem
coverPreserving_opens_map
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/Sites.lean
[]
[ "Opens.grothendieckTopology" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isTerminalOfEmpty (F : Sheaf C X) : Limits.IsTerminal (F.obj.obj (op ⊥))
F.isTerminalOfBotCover ⊥ (fun _ h => h.elim)
def
TopCat.Sheaf.isTerminalOfEmpty
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/Sites.lean
[]
[]
The empty component of a sheaf is terminal.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isTerminalOfEqEmpty (F : X.Sheaf C) {U : Opens X} (h : U = ⊥) : Limits.IsTerminal (F.obj.obj (op U))
by convert! F.isTerminalOfEmpty
def
TopCat.Sheaf.isTerminalOfEqEmpty
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/Sites.lean
[]
[]
A variant of `isTerminalOfEmpty` that is easier to `apply`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
restrictHomEquivHom (h : Opens.IsBasis (Set.range B)) : ((inducedFunctor B).op ⋙ F ⟶ (inducedFunctor B).op ⋙ F'.1) ≃ (F ⟶ F'.1)
@Functor.IsCoverDense.restrictHomEquivHom _ _ _ _ _ _ _ _ (Opens.coverDense_inducedFunctor h) _ F F'
def
TopCat.Sheaf.restrictHomEquivHom
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/Sites.lean
[]
[ "Set.range" ]
If a family `B` of open sets forms a basis of the topology on `X`, and if `F'` is a sheaf on `X`, then a homomorphism between a presheaf `F` on `X` and `F'` is equivalent to a homomorphism between their restrictions to the indexing type `ι` of `B`, with the induced category structure on `ι`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
extend_hom_app (h : Opens.IsBasis (Set.range B)) (α : (inducedFunctor B).op ⋙ F ⟶ (inducedFunctor B).op ⋙ F'.1) (i : ι) : (restrictHomEquivHom F F' h α).app (op (B i)) = α.app (op i)
by nth_rw 2 [← (restrictHomEquivHom F F' h).left_inv α] rfl
theorem
TopCat.Sheaf.extend_hom_app
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/Sites.lean
[]
[ "Set.range" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
hom_ext (h : Opens.IsBasis (Set.range B)) {α β : F ⟶ F'.1} (he : ∀ i, α.app (op (B i)) = β.app (op (B i))) : α = β
by apply (restrictHomEquivHom F F' h).symm.injective ext i exact he i.unop
theorem
TopCat.Sheaf.hom_ext
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/Sites.lean
[]
[ "Set.range" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isIso_iff_isIso_basis {F G : Sheaf C X} (h : Opens.IsBasis (Set.range B)) {φ : F ⟶ G} (hi : ∀ i, IsIso (φ.hom.app (op (B i)))) : IsIso φ
by have : (inducedFunctor B).IsCoverDense (Opens.grothendieckTopology X) := Opens.coverDense_inducedFunctor h refine Functor.IsCoverDense.iso_of_restrict_iso (G := inducedFunctor B) _ ?_ rw [NatTrans.isIso_iff_isIso_app] exact fun _ ↦ hi _
theorem
TopCat.Sheaf.isIso_iff_isIso_basis
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/Sites.lean
[]
[ "Opens.grothendieckTopology", "Set.range" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
IsCompatible (sf : ∀ i : ι, ToType (F.obj (op (U i)))) : Prop
∀ i j : ι, F.map (infLELeft (U i) (U j)).op (sf i) = F.map (infLERight (U i) (U j)).op (sf j)
def
TopCat.Presheaf.IsCompatible
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/UniqueGluing.lean
[]
[]
A family of sections `sf` is compatible, if the restrictions of `sf i` and `sf j` to `U i ⊓ U j` agree, for all `i` and `j`
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
IsGluing (sf : ∀ i : ι, ToType (F.obj (op (U i)))) (s : ToType (F.obj (op (iSup U)))) : Prop
∀ i : ι, F.map (Opens.leSupr U i).op s = sf i
def
TopCat.Presheaf.IsGluing
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/UniqueGluing.lean
[]
[ "iSup" ]
A section `s` is a gluing for a family of sections `sf` if it restricts to `sf i` on `U i`, for all `i`
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
IsSheafUniqueGluing : Prop
∀ ⦃ι : Type x⦄ (U : ι → Opens X) (sf : ∀ i : ι, ToType (F.obj (op (U i)))), IsCompatible F U sf → ∃! s : ToType (F.obj (op (iSup U))), IsGluing F U sf s
def
TopCat.Presheaf.IsSheafUniqueGluing
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/UniqueGluing.lean
[]
[ "iSup" ]
The sheaf condition in terms of unique gluings. A presheaf `F : Presheaf C X` satisfies this sheaf condition if and only if, for every compatible family of sections `sf : Π i : ι, F.obj (op (U i))`, there exists a unique gluing `s : F.obj (op (iSup U))`. We prove this to be equivalent to the usual one below in `TopCat...
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
objPairwiseOfFamily (sf : ∀ i, F.obj (op (U i))) : ∀ i, ((Pairwise.diagram U).op ⋙ F).obj i
| ⟨Pairwise.single i⟩ => sf i | ⟨Pairwise.pair i j⟩ => F.map (infLELeft (U i) (U j)).op (sf i)
def
TopCat.Presheaf.objPairwiseOfFamily
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/UniqueGluing.lean
[]
[]
Given sections over a family of open sets, extend it to include sections over pairwise intersections of the open sets.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
IsCompatible.sectionPairwise {sf} (h : IsCompatible F U sf) : ((Pairwise.diagram U).op ⋙ F).sections
by refine ⟨objPairwiseOfFamily sf, ?_⟩ let G := (Pairwise.diagram U).op ⋙ F rintro (i | ⟨i, j⟩) (i' | ⟨i', j'⟩) (_ | _ | _ | _) · exact ConcreteCategory.congr_hom (G.map_id <| op <| Pairwise.single i) _ · rfl · exact (h i' i).symm · exact ConcreteCategory.congr_hom (G.map_id <| op <| Pairwise.pair i j) _
def
TopCat.Presheaf.IsCompatible.sectionPairwise
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/UniqueGluing.lean
[]
[ "symm" ]
Given a compatible family of sections over open sets, extend it to a section of the functor `(Pairwise.diagram U).op ⋙ F`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isGluing_iff_pairwise {sf s} : IsGluing F U sf s ↔ ∀ i, (F.mapCone (Pairwise.cocone U).op).π.app i s = objPairwiseOfFamily sf i
by refine ⟨fun h ↦ ?_, fun h i ↦ h (op <| Pairwise.single i)⟩ rintro (i | ⟨i, j⟩) · exact h i · rw [← (F.mapCone (Pairwise.cocone U).op).w (op <| Pairwise.Hom.left i j)] exact congr_arg _ (h i)
theorem
TopCat.Presheaf.isGluing_iff_pairwise
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/UniqueGluing.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
IsSheaf.isSheafUniqueGluing_types (h : F.IsSheaf) (sf : ∀ i : ι, F.obj (op (U i))) (cpt : IsCompatible F U sf) : ∃! s : F.obj (op (iSup U)), IsGluing F U sf s
by simp_rw [isGluing_iff_pairwise] exact (Types.isLimit_iff _).mp (h.isSheafPairwiseIntersections U) _ cpt.sectionPairwise.prop
theorem
TopCat.Presheaf.IsSheaf.isSheafUniqueGluing_types
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/UniqueGluing.lean
[]
[ "iSup" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isSheaf_iff_isSheafUniqueGluing_types : F.IsSheaf ↔ F.IsSheafUniqueGluing
by simp_rw [isSheaf_iff_isSheafPairwiseIntersections, IsSheafPairwiseIntersections, Types.isLimit_iff, IsSheafUniqueGluing, isGluing_iff_pairwise] refine forall₂_congr fun ι U ↦ ⟨fun h sf cpt ↦ ?_, fun h s hs ↦ ?_⟩ · exact h _ cpt.sectionPairwise.prop · specialize h (fun i ↦ s <| op <| Pairwise.single i) fu...
theorem
TopCat.Presheaf.isSheaf_iff_isSheafUniqueGluing_types
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/UniqueGluing.lean
[]
[ "symm", "trans" ]
For type-valued presheaves, the sheaf condition in terms of unique gluings is equivalent to the usual sheaf condition.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isSheaf_of_isSheafUniqueGluing_types (Fsh : F.IsSheafUniqueGluing) : F.IsSheaf
(isSheaf_iff_isSheafUniqueGluing_types F).mpr Fsh
theorem
TopCat.Presheaf.isSheaf_of_isSheafUniqueGluing_types
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/UniqueGluing.lean
[]
[]
The usual sheaf condition can be obtained from the sheaf condition in terms of unique gluings.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
IsSheaf.isSheafUniqueGluing (h : F.IsSheaf) {ι : Type*} (U : ι → Opens X) (sf : ∀ i : ι, ToType (F.obj (op (U i)))) (cpt : IsCompatible F U sf) : ∃! s : ToType (F.obj (op (iSup U))), IsGluing F U sf s
((isSheaf_iff_isSheaf_comp' (forget C) F).mp h).isSheafUniqueGluing_types sf cpt
theorem
TopCat.Presheaf.IsSheaf.isSheafUniqueGluing
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/UniqueGluing.lean
[]
[ "iSup" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isSheaf_iff_isSheafUniqueGluing : F.IsSheaf ↔ F.IsSheafUniqueGluing
Iff.trans (isSheaf_iff_isSheaf_comp' (forget C) F) (isSheaf_iff_isSheafUniqueGluing_types (F ⋙ forget C))
theorem
TopCat.Presheaf.isSheaf_iff_isSheafUniqueGluing
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/UniqueGluing.lean
[]
[]
For presheaves valued in a concrete category, whose forgetful functor reflects isomorphisms and preserves limits, the sheaf condition in terms of unique gluings is equivalent to the usual one.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
existsUnique_gluing (sf : ∀ i : ι, ToType (F.1.obj (op (U i)))) (h : IsCompatible F.1 U sf) : ∃! s : ToType (F.1.obj (op (iSup U))), IsGluing F.1 U sf s
IsSheaf.isSheafUniqueGluing F.property U sf h
theorem
TopCat.Sheaf.existsUnique_gluing
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/UniqueGluing.lean
[]
[ "iSup" ]
A more convenient way of obtaining a unique gluing of sections for a sheaf.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
existsUnique_gluing' (V : Opens X) (iUV : ∀ i : ι, U i ⟶ V) (hcover : V ≤ iSup U) (sf : ∀ i : ι, ToType (F.1.obj (op (U i)))) (h : IsCompatible F.1 U sf) : ∃! s : ToType (F.1.obj (op V)), ∀ i : ι, F.1.map (iUV i).op s = sf i
by have V_eq_supr_U : V = iSup U := le_antisymm hcover (iSup_le fun i => (iUV i).le) obtain ⟨gl, gl_spec, gl_uniq⟩ := F.existsUnique_gluing U sf h refine ⟨F.1.map (eqToHom V_eq_supr_U).op gl, ?_, ?_⟩ · intro i rw [← ConcreteCategory.comp_apply, ← F.1.map_comp] exact gl_spec i · intro gl' gl'_spec ...
theorem
TopCat.Sheaf.existsUnique_gluing'
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/UniqueGluing.lean
[]
[ "iSup", "iSup_le", "le_antisymm" ]
In this version of the lemma, the inclusion homs `iUV` can be specified directly by the user, which can be more convenient in practice.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
eq_of_locally_eq (s t : ToType (F.1.obj (op (iSup U)))) (h : ∀ i, F.1.map (Opens.leSupr U i).op s = F.1.map (Opens.leSupr U i).op t) : s = t
by let sf : ∀ i : ι, ToType (F.1.obj (op (U i))) := fun i => F.1.map (Opens.leSupr U i).op s have sf_compatible : IsCompatible _ U sf := by intro i j simp_rw [sf, ← ConcreteCategory.comp_apply, ← F.1.map_comp] rfl obtain ⟨gl, -, gl_uniq⟩ := F.existsUnique_gluing U sf sf_compatible trans gl · apply...
theorem
TopCat.Sheaf.eq_of_locally_eq
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/UniqueGluing.lean
[]
[ "iSup", "symm", "trans" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
eq_of_locally_eq' (V : Opens X) (iUV : ∀ i : ι, U i ⟶ V) (hcover : V ≤ iSup U) (s t : ToType (F.1.obj (op V))) (h : ∀ i, F.1.map (iUV i).op s = F.1.map (iUV i).op t) : s = t
by have V_eq_supr_U : V = iSup U := le_antisymm hcover (iSup_le fun i => (iUV i).le) suffices F.1.map (eqToHom V_eq_supr_U.symm).op s = F.1.map (eqToHom V_eq_supr_U.symm).op t by convert! congr_arg (F.1.map (eqToHom V_eq_supr_U).op) this <;> rw [← ConcreteCategory.comp_apply, ← F.1.map_comp, eqToHom_op, eqT...
theorem
TopCat.Sheaf.eq_of_locally_eq'
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/UniqueGluing.lean
[]
[ "iSup", "iSup_le", "le_antisymm" ]
In this version of the lemma, the inclusion homs `iUV` can be specified directly by the user, which can be more convenient in practice.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
eq_of_locally_eq₂ {U₁ U₂ V : Opens X} (i₁ : U₁ ⟶ V) (i₂ : U₂ ⟶ V) (hcover : V ≤ U₁ ⊔ U₂) (s t : ToType (F.1.obj (op V))) (h₁ : F.1.map i₁.op s = F.1.map i₁.op t) (h₂ : F.1.map i₂.op s = F.1.map i₂.op t) : s = t
by classical fapply F.eq_of_locally_eq' fun t : Bool => if t then U₁ else U₂ · exact fun i => if h : i then eqToHom (if_pos h) ≫ i₁ else eqToHom (if_neg h) ≫ i₂ · refine le_trans hcover ?_ rw [sup_le_iff] constructor · exact le_iSup (fun t : Bool => if t then U₁ else U₂) true · exa...
theorem
TopCat.Sheaf.eq_of_locally_eq₂
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/UniqueGluing.lean
[]
[ "le_iSup", "le_trans", "sup_le_iff" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
eq_app_of_locally_eq {V : Opens X} {G : Sheaf C X} {f : F ⟶ G} {s : ToType (F.1.obj (op (iSup U)))} {t : ToType (G.1.obj (op V))} {sf : ∀ i : ι, ToType (F.1.obj (op (U i)))} (h : IsGluing F.1 U sf s) (hV : ∀ i : ι, U i ≤ V) (ht : ∀ i : ι, f.1.app (op (U i)) (sf i) = G.1.map (homOfLE (hV i)).op t) : f.ho...
by refine eq_of_locally_eq G U _ _ (fun _ ↦ ?_) rw [← NatTrans.naturality_apply, h, ht, ← ConcreteCategory.comp_apply, ← Functor.map_comp] rfl
theorem
TopCat.Sheaf.eq_app_of_locally_eq
Topology.Sheaves.SheafCondition
Mathlib/Topology/Sheaves/SheafCondition/UniqueGluing.lean
[]
[ "iSup" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
SpectralSpace (X : Type*) [TopologicalSpace X] : Prop extends T0Space X, CompactSpace X, QuasiSober X, QuasiSeparatedSpace X, PrespectralSpace X
class
SpectralSpace
Topology.Spectral
Mathlib/Topology/Spectral/Basic.lean
[]
[ "CompactSpace", "PrespectralSpace", "QuasiSeparatedSpace", "QuasiSober", "T0Space", "TopologicalSpace" ]
A topological space is spectral if it is T0, compact, sober, quasi-separated, and its compact open subsets form an open basis.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Topology.IsOpenEmbedding.spectralSpace [SpectralSpace Y] [CompactSpace X] (hf : IsOpenEmbedding f) : SpectralSpace X
where __ := hf.quasiSober __ := hf.prespectralSpace __ := hf.quasiSeparatedSpace __ := hf.isEmbedding.t0Space
theorem
Topology.IsOpenEmbedding.spectralSpace
Topology.Spectral
Mathlib/Topology/Spectral/Basic.lean
[]
[ "CompactSpace", "SpectralSpace" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
constructibleTopologySubbasis (X : Type*) [TopologicalSpace X] : Set (Set X)
{ s | IsOpen s ∧ IsCompact s } ∪ { s | IsClosed s ∧ IsCompact sᶜ }
def
constructibleTopologySubbasis
Topology.Spectral
Mathlib/Topology/Spectral/ConstructibleTopology.lean
[]
[ "IsClosed", "IsCompact", "IsOpen", "Set", "TopologicalSpace" ]
The subbasis of the constructible topology on a topological space `X`: It consists of the open and compact sets of `X` and their complements.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319