mathlib-initiative/mathlib-tactics huggingface dataset:
Module: Mathlib.RingTheory.Finiteness.FiniteTypeLocal

Goal state before:
pp: R : Type u_1
S : Type u_2
inst✝² : CommRing R
inst✝¹ : CommRing S
inst✝ : Algebra R S
s✝ : Set R
hs✝ : Ideal.span s✝ = ⊤
s : Finset R
h₁ : ↑s ⊆ s✝
hs : Ideal.span ↑s = ⊤
h : ∀ (i : ↥s), FiniteType (Localization.Away ↑i) (Localization.Away ↑i ⊗[R] S)
f : R →+* S := algebraMap R S
this : (r : ↥s) → Algebra (Localization.Away ↑r) (Localization.Away (f ↑r))
s₁ : (r : ↥s) → Finset (Localization.Away ↑r ⊗[R] S)
s₂ : ∀ (r : ↥s), adjoin (Localization.Away ↑r) ↑(s₁ r) = ⊤
⊢ ⊤.FG

Tactic:
let sf := fun x : s => IsLocalization.finsetIntegerMultiple (Submonoid.powers (f x)) (s₁ x)

Goal state after:
R : Type u_1
S : Type u_2
inst✝² : CommRing R
inst✝¹ : CommRing S
inst✝ : Algebra R S
s✝ : Set R
hs✝ : Ideal.span s✝ = ⊤
s : Finset R
h₁ : ↑s ⊆ s✝
hs : Ideal.span ↑s = ⊤
h : ∀ (i : ↥s), FiniteType (Localization.Away ↑i) (Localization.Away ↑i ⊗[R] S)
f : R →+* S := algebraMap R S
this : (r : ↥s) → Algebra (Localization.Away ↑r) (Localization.Away (f ↑r))
s₁ : (r : ↥s) → Finset (Localization.Away ↑r ⊗[R] S)
s₂ : ∀ (r : ↥s), adjoin (Localization.Away ↑r) ↑(s₁ r) = ⊤
sf : ↥s → Finset S := fun x ↦ IsLocalization.finsetIntegerMultiple (Submonoid.powers (f ↑x)) (s₁ x)
⊢ ⊤.FG
Module: Mathlib.RingTheory.RingHom.Finite

Goal state before:
pp: R S : Type u_5
inst✝¹ : CommRing R
inst✝ : CommRing S
f : R →+* S
s : Finset R
hs : Ideal.span ↑s = ⊤
this✝² : Algebra R S := f.toAlgebra
this✝¹ : (r : ↥s) → Algebra (Localization.Away ↑r) (Localization.Away (f ↑r)) :=
  fun r ↦ (Localization.awayMap f ↑r).toAlgebra
this✝ : ∀ (r : ↥s), IsLocalization (Submonoid.map (algebraMap R S) (Submonoid.powers ↑r)) (Localization.Away (f ↑r))
this : ∀ (r : ↥s), IsScalarTower R (Localization.Away ↑r) (Localization.Away (f ↑r))
s₁ : (r : ↥s) → Finset (Localization.Away (f ↑r))
s₂ : ∀ (r : ↥s), Submodule.span (Localization.Away ↑r) ↑(s₁ r) = ⊤
⊢ ⊤.FG

Tactic:
let sf := fun x : s => IsLocalization.finsetIntegerMultiple (Submonoid.powers (f x)) (s₁ x)

Goal state after:
R S : Type u_5
inst✝¹ : CommRing R
inst✝ : CommRing S
f : R →+* S
s : Finset R
hs : Ideal.span ↑s = ⊤
this✝² : Algebra R S := f.toAlgebra
this✝¹ : (r : ↥s) → Algebra (Localization.Away ↑r) (Localization.Away (f ↑r)) :=
  fun r ↦ (Localization.awayMap f ↑r).toAlgebra
this✝ : ∀ (r : ↥s), IsLocalization (Submonoid.map (algebraMap R S) (Submonoid.powers ↑r)) (Localization.Away (f ↑r))
this : ∀ (r : ↥s), IsScalarTower R (Localization.Away ↑r) (Localization.Away (f ↑r))
s₁ : (r : ↥s) → Finset (Localization.Away (f ↑r))
s₂ : ∀ (r : ↥s), Submodule.span (Localization.Away ↑r) ↑(s₁ r) = ⊤
sf : ↥s → Finset S := fun x ↦ IsLocalization.finsetIntegerMultiple (Submonoid.powers (f ↑x)) (s₁ x)
⊢ ⊤.FG
Module: Mathlib.AlgebraicGeometry.Morphisms.FiniteType

Goal state before:
pp: case inr
X : Scheme
R : CommRingCat
f : X ⟶ Spec R
inst✝¹ : LocallyOfFiniteType f
inst✝ : JacobsonSpace ↥(Spec R)
this :
  ∀ {X : Scheme} (R : CommRingCat) (f : X ⟶ Spec R) [LocallyOfFiniteType f] [JacobsonSpace ↥(Spec R)],
    (∃ S, X = Spec S) → JacobsonSpace ↥X
hX : ¬∃ S, X = Spec S
inst : JacobsonSpace ↥(Spec R)
⊢ JacobsonSpace ↥X

Tactic:
X.affineCover.isOpenCover_opensRange.jacobsonSpace_iff

Goal state after:
case inr
X : Scheme
R : CommRingCat
f : X ⟶ Spec R
inst✝¹ : LocallyOfFiniteType f
inst✝ : JacobsonSpace ↥(Spec R)
this :
  ∀ {X : Scheme} (R : CommRingCat) (f : X ⟶ Spec R) [LocallyOfFiniteType f] [JacobsonSpace ↥(Spec R)],
    (∃ S, X = Spec S) → JacobsonSpace ↥X
hX : ¬∃ S, X = Spec S
inst : JacobsonSpace ↥(Spec R)
⊢ ∀ (i : X.affineCover.I₀), JacobsonSpace ↥(Scheme.Hom.opensRange (X.affineCover.f i))
Module: Mathlib.LinearAlgebra.Charpoly.BaseChange

Goal state before:
pp: R : Type u_1
M : Type u_2
inst✝⁴ : CommRing R
inst✝³ : AddCommGroup M
inst✝² : Module R M
inst✝¹ : Module.Free R M
inst✝ : Module.Finite R M
f : M →ₗ[R] M
⊢ LinearMap.det f = (-1) ^ Module.finrank R M * f.charpoly.coeff 0

Tactic:
nontriviality R

Goal state after:
R : Type u_1
M : Type u_2
inst✝⁴ : CommRing R
inst✝³ : AddCommGroup M
inst✝² : Module R M
inst✝¹ : Module.Free R M
inst✝ : Module.Finite R M
f : M →ₗ[R] M
a✝ : Nontrivial R
⊢ LinearMap.det f = (-1) ^ Module.finrank R M * f.charpoly.coeff 0
Module: Mathlib.AlgebraicGeometry.Morphisms.Separated

Goal state before:
pp: X Y Z : Scheme
f : X ⟶ Y
g : Y ⟶ Z
inst✝ : IsSeparated (f ≫ g)
this : IsClosedImmersion (pullback.diagonal (f ≫ g))
⊢ IsSeparated f

Tactic:
pullback.diagonal_comp

Goal state after:
X Y Z : Scheme
f : X ⟶ Y
g : Y ⟶ Z
inst✝ : IsSeparated (f ≫ g)
this :
  IsClosedImmersion
    (pullback.diagonal f ≫
      (pullbackDiagonalMapIdIso f f g).inv ≫
        pullback.snd (pullback.diagonal g) (pullback.map (f ≫ g) (f ≫ g) g g f f (𝟙 Z) ⋯ ⋯))
⊢ IsSeparated f
Module: Mathlib.RingTheory.Spectrum.Prime.Polynomial

Goal state before:
pp: case mp
R : Type u_2
A : Type u_1
inst✝² : CommRing R
inst✝¹ : CommRing A
inst✝ : Algebra R A
f : A
s : Set A
x : PrimeSpectrum R
⊢ x ∈ comap (algebraMap R A) '' (zeroLocus s \ zeroLocus {f}) →
    ¬IsNilpotent ((algebraMap A ((A ⧸ Ideal.span s) ⊗[R] x.asIdeal.ResidueField)) f)

Tactic:
rintro ⟨q, ⟨hqg, hqf⟩, rfl⟩ H
    simp only [mem_zeroLocus, Set.singleton_subset_iff, SetLike.mem_coe] at hqg hqf
    have hs : Ideal.span s ≤ RingHom.ker (algebraMap A q.asIdeal.ResidueField) := by
      rwa [Ideal.span_le, Ideal.ker_algebraMap_residueField]
    let F : (A ⧸ Ideal.span s) ⊗[R] (q.asIdeal.comap (algebraMap R A)).ResidueField →ₐ[A]
        q.asIdeal.ResidueField :=
      Algebra.TensorProduct.lift
        (Ideal.Quotient.liftₐ (Ideal.span s) (Algebra.ofId A _) hs)
        (Ideal.ResidueField.mapₐ _ _ (Algebra.ofId _ _) rfl)
        fun _ _ ↦ .all _ _
    have := H.map F
    rw [AlgHom.commutes, isNilpotent_iff_eq_zero, ← RingHom.mem_ker,
      Ideal.ker_algebraMap_residueField] at this
    exact hqf this

Goal state after:
Module: Mathlib.AlgebraicGeometry.Geometrically.Basic

Goal state before:
pp: P : ObjectProperty Scheme
X Y : Scheme
f : X ⟶ Y
inst✝ : P.IsClosedUnderIsomorphisms
⊢ geometrically P f ↔ ∀ (K : Type u) [inst : Field K] (y : Spec (of K) ⟶ Y), P (pullback f y)

Tactic:
refine ⟨fun h K _ _ ↦ pullback_of_geometrically h _ _, fun H K _ _ Y fst snd h ↦ ?_⟩

Goal state after:
P : ObjectProperty Scheme
X Y✝ : Scheme
f : X ⟶ Y✝
inst✝ : P.IsClosedUnderIsomorphisms
H : ∀ (K : Type u) [inst : Field K] (y : Spec (of K) ⟶ Y✝), P (pullback f y)
K : Type u
x✝¹ : Field K
x✝ : Spec (of K) ⟶ Y✝
Y : Scheme
fst : Y ⟶ X
snd : Y ⟶ Spec (of K)
h : IsPullback fst snd f x✝
⊢ P Y
Module: Mathlib.AlgebraicGeometry.Morphisms.UniversallyClosed

Goal state before:
pp: X Y : Scheme
f : X ⟶ Y
⊢ IsZariskiLocalAtTarget @UniversallyClosed

Tactic:
by
  rw [universallyClosed_eq]
  apply universally_isZariskiLocalAtTarget
  intro X Y f ι U hU H
  simp_rw [topologically, morphismRestrict_base] at H
  exact hU.isClosedMap_iff_restrictPreimage.mpr H

Goal state after:
Module: Mathlib.RingTheory.RingHom.Integral

Goal state before:
pp: R S : Type u_1
inst✝¹ : CommRing R
inst✝ : CommRing S
f : R →+* S
s : Set R
hs : Ideal.span s = ⊤
H : ∀ (r : ↑s), (fun {R S} [CommRing R] [CommRing S] x ↦ x.IsIntegral) (Localization.awayMap f ↑r)
r : S
this : Algebra R S := f.toAlgebra
⊢ f.IsIntegralElem r

Tactic:
change r ∈ (integralClosure R S).toSubmodule

Goal state after:
R S : Type u_1
inst✝¹ : CommRing R
inst✝ : CommRing S
f : R →+* S
s : Set R
hs : Ideal.span s = ⊤
H : ∀ (r : ↑s), (fun {R S} [CommRing R] [CommRing S] x ↦ x.IsIntegral) (Localization.awayMap f ↑r)
r : S
this : Algebra R S := f.toAlgebra
⊢ r ∈ Subalgebra.toSubmodule (integralClosure R S)
Module: Mathlib.AlgebraicGeometry.Morphisms.Finite

Goal state before:
pp: case inr
S : CommRingCat
inst✝² : JacobsonSpace ↥(Spec S)
R : CommRingCat
inst✝¹ : Subsingleton ↥(Spec R)
inst✝ : IsReduced (Spec R)
h✝ : Nonempty ↥(Spec R)
this✝ : IrreducibleSpace ↥(Spec R)
this : IsDomain ↑R
φ : S ⟶ R
⊢ IsFinite (Spec.map φ) ↔ LocallyOfFiniteType (Spec.map φ)

Tactic:
IsFinite.SpecMap_iff,

Goal state after:
case inr
S : CommRingCat
inst✝² : JacobsonSpace ↥(Spec S)
R : CommRingCat
inst✝¹ : Subsingleton ↥(Spec R)
inst✝ : IsReduced (Spec R)
h✝ : Nonempty ↥(Spec R)
this✝ : IrreducibleSpace ↥(Spec R)
this : IsDomain ↑R
φ : S ⟶ R
⊢ (CommRingCat.Hom.hom φ).Finite ↔ LocallyOfFiniteType (Spec.map φ)
Module: Mathlib.AlgebraicGeometry.Morphisms.Flat

Goal state before:
pp: case inr
X Y : Scheme
f : X ⟶ Y
inst✝² : Flat f
inst✝¹ : QuasiCompact f
inst✝ : Surjective f
s : Set ↥Y
hs : IsOpen (⇑f ⁻¹' s)
this :
  ∀ {X Y : Scheme} (f : X ⟶ Y) [Flat f] [QuasiCompact f] [Surjective f] (s : Set ↥Y),
    IsOpen (⇑f ⁻¹' s) → (∃ R, Y = Spec R) → IsOpen s
hY : ¬∃ R, Y = Spec R
𝒰 : Y.OpenCover := Y.affineCover
i : 𝒰.I₀
⊢ IsOpen (⇑(pullback.snd (𝒰.f i) f) ⁻¹' ⇑f ⁻¹' s)

Tactic:
exact hs.preimage (Scheme.Hom.continuous _)

Goal state after:
Module: Mathlib.AlgebraicGeometry.AffineSpace

Goal state before:
pp: n : Type u
S T : Scheme
f : S ⟶ T
⊢ IsPullback (map n f) (𝔸(n; S) ↘ S) (𝔸(n; T) ↘ T) f

Tactic:
refine (IsPullback.paste_horiz_iff (.flip <| .of_hasPullback _ _) (map_over f)).mp ?_
  simp only [terminal.comp_from, ]
  convert! (IsPullback.of_hasPullback _ _).flip
  rw [← toSpecMvPoly, ← toSpecMvPoly, map_toSpecMvPoly]

Goal state after:
Module: Mathlib.CategoryTheory.Limits.Types.ColimitTypeFiltered

Goal state before:
pp: J : Type u
inst✝¹ : Category.{v, u} J
inst✝ : IsFiltered J
F : J ⥤ Type w₀
c : F.CoconeTypes
h :
  ∀ (j : J) (x x' : F.obj j),
    c.ι j x = c.ι j x' → ∃ k f, (ConcreteCategory.hom (F.map f)) x = (ConcreteCategory.hom (F.map f)) x'
j j' : J
x : F.obj j
x' : F.obj j'
eq✝ : c.ι j x = c.ι j' x'
k : J
g : IsFiltered.max j j' ⟶ k
eq :
  (ConcreteCategory.hom (F.map g)) ((ConcreteCategory.hom (F.map (leftToMax j j'))) x) =
    (ConcreteCategory.hom (F.map g)) ((ConcreteCategory.hom (F.map (rightToMax j j'))) x')
⊢ (ConcreteCategory.hom (F.map (leftToMax j j' ≫ g))) x = (ConcreteCategory.hom (F.map (rightToMax j j' ≫ g))) x'

Tactic:
simp [eq]

Goal state after:
Module: Mathlib.Topology.LocallyFinsupp

Goal state before:
pp: case left
X : Type u_1
inst✝¹ : TopologicalSpace X
U : Set X
Y : Type u_2
inst✝ : AddMonoid Y
f g : X → Y
hf : f ∈ {f | Function.support f ⊆ U ∧ ∀ z ∈ U, ∃ t ∈ 𝓝 z, (t ∩ Function.support f).Finite}
hg : g ∈ {f | Function.support f ⊆ U ∧ ∀ z ∈ U, ∃ t ∈ 𝓝 z, (t ∩ Function.support f).Finite}
x : X
hx : x ∉ U
⊢ x ∉ Function.support (f + g)

Tactic:
simp [notMem_support.1 fun a ↦ hx (hf.1 a), notMem_support.1 fun a ↦ hx (hg.1 a)]

Goal state after:
Module: Mathlib.AlgebraicGeometry.Morphisms.Flat

Goal state before:
pp: X Y S T : Scheme
f : T ⟶ S
g : Y ⟶ X
iX : X ⟶ S
iY : Y ⟶ T
H : IsPullback g iY iX f
US : S.Opens
UT : T.Opens
UX : X.Opens
hUST : UT ≤ f ⁻¹ᵁ US
hUSX : UX ≤ iX ⁻¹ᵁ US
UY : Y.Opens
hUY : UY = g ⁻¹ᵁ UX ⊓ iY ⁻¹ᵁ UT
ι : Type u
inst✝ : Finite ι
VX : ι → X.Opens
hVU : iSup VX = UX
hV : ∀ (i : ι), IsIso (pushoutSection H hUST ⋯ ⋯)
hV' : ∀ (i j : ι), Mono (pushoutSection H hUST ⋯ ⋯)
hT : (CommRingCat.Hom.hom (Scheme.Hom.appLE f US UT hUST)).Flat
D : CategoryTheory.Pairwise ι ⥤ X.Opens := Pairwise.diagram VX
h : iSup D.obj = UX
c₀ : Cocone D := (colimit.cocone D).extend (eqToIso ⋯).hom
F : (CategoryTheory.Pairwise ι)ᵒᵖ ⥤ CommRingCat :=
  Under.lift (D.op ⋙ X.presheaf)
      ((Functor.const (CategoryTheory.Pairwise ι)ᵒᵖ).map (Scheme.Hom.appLE iX US UX hUSX) ≫
        (Functor.mapCone X.presheaf c₀.op).π) ⋙
    Under.pushout (Scheme.Hom.appLE f US UT hUST) ⋙ Under.forget Γ(T, UT)
G : X.Opens ⥤ Y.Opens :=
  { obj := fun U ↦ g ⁻¹ᵁ U ⊓ iY ⁻¹ᵁ UT, map := fun {X_1 Y_1} h ↦ homOfLE ⋯, map_id := ⋯, map_comp := ⋯ }
αF : F ⟶ D.op ⋙ G.op ⋙ Y.presheaf :=
  { app := fun i ↦ (pushout.congrHom ⋯ ⋯).hom ≫ pushoutSection H hUST ⋯ ⋯, naturality := ⋯ }
c : Cone F :=
  (Under.pushout (Scheme.Hom.appLE f US UT hUST) ⋙ Under.forget Γ(T, UT)).mapCone
    (Under.liftCone (Functor.mapCone X.presheaf c₀.op) (Scheme.Hom.appLE iX US UX hUSX))
this : PreservesFiniteLimits (Under.pushout (Scheme.Hom.appLE f US UT hUST))
val✝ : Fintype ι
hc : IsLimit c :=
  isLimitOfPreserves (Under.pushout (Scheme.Hom.appLE f US UT hUST) ⋙ Under.forget Γ(T, UT))
    (Under.isLimitLiftCone (Functor.mapCone X.presheaf c₀.op) (Scheme.Hom.appLE iX US UX hUSX) ⋯.some)
c'₀ : Cocone (D ⋙ G) := (colimit.cocone (D ⋙ G)).extend (eqToIso ⋯).hom
c' : Cone (D.op ⋙ G.op ⋙ Y.presheaf) := Functor.mapCone Y.presheaf c'₀.op
i j : ι
⊢ (D ⋙ G).obj (Pairwise.pair i j) = (Pairwise.diagram fun i ↦ g ⁻¹ᵁ VX i ⊓ iY ⁻¹ᵁ UT).obj (Pairwise.pair i j)

Tactic:
by
        dsimp [D, G]; rw [Scheme.Hom.preimage_inf, inf_inf_distrib_right]

Goal state after:
Module: Mathlib.AlgebraicGeometry.Birational.RationalMap

Goal state before:
pp: X Y S : Scheme
inst✝² : X.Over S
inst✝¹ : Y.Over S
f : X.PartialMap Y
inst✝ : RationalMap.IsOver S f.toRationalMap
f' : X.PartialMap Y
hf₁ : IsOver S f'
hf₂ : f'.toRationalMap = f.toRationalMap
U : X.Opens
hU : Dense ↑U
hUl : U ≤ f'.domain
hUr : U ≤ f.domain
e : (f'.restrict U hU hUl).hom = (f.restrict U hU hUr).hom
⊢ Hom.IsOver (f.restrict U hU hUr).hom S

Tactic:
← e

Goal state after:
X Y S : Scheme
inst✝² : X.Over S
inst✝¹ : Y.Over S
f : X.PartialMap Y
inst✝ : RationalMap.IsOver S f.toRationalMap
f' : X.PartialMap Y
hf₁ : IsOver S f'
hf₂ : f'.toRationalMap = f.toRationalMap
U : X.Opens
hU : Dense ↑U
hUl : U ≤ f'.domain
hUr : U ≤ f.domain
e : (f'.restrict U hU hUl).hom = (f.restrict U hU hUr).hom
⊢ Hom.IsOver (f'.restrict U hU hUl).hom S
Module: Mathlib.AlgebraicGeometry.Birational.Composition

Goal state before:
pp: X Y Z : Scheme
inst✝³ : PreirreducibleSpace ↥X
inst✝² : Nonempty ↥Y
f₁ f₂ : X.PartialMap Y
inst✝¹ : IsDominant f₁.hom
inst✝ : IsDominant f₂.hom
g : Y.PartialMap Z
W : X.Opens
hW : Dense ↑W
hW₁ : W ≤ f₁.domain
hW₂ : W ≤ f₂.domain
e : (f₁.comp g).restrict (f₁.domain.ι ''ᵁ f₁.hom ⁻¹ᵁ g.domain ⊓ W) ⋯ ⋯ = (f₂.restrict W hW hW₂).comp g
⊢ (f₁.comp g).equiv (f₂.comp g)

Tactic:
comp_restrict_left

Goal state after:
X Y Z : Scheme
inst✝³ : PreirreducibleSpace ↥X
inst✝² : Nonempty ↥Y
f₁ f₂ : X.PartialMap Y
inst✝¹ : IsDominant f₁.hom
inst✝ : IsDominant f₂.hom
g : Y.PartialMap Z
W : X.Opens
hW : Dense ↑W
hW₁ : W ≤ f₁.domain
hW₂ : W ≤ f₂.domain
e :
  (f₁.comp g).restrict (f₁.domain.ι ''ᵁ f₁.hom ⁻¹ᵁ g.domain ⊓ W) ⋯ ⋯ =
    (f₂.comp g).restrict (f₂.domain.ι ''ᵁ f₂.hom ⁻¹ᵁ g.domain ⊓ W) ⋯ ⋯
⊢ (f₁.comp g).equiv (f₂.comp g)
Module: Mathlib.AlgebraicGeometry.Morphisms.UniversallyInjective

Goal state before:
pp: X Y : Scheme
f : X ⟶ Y
⊢ [UniversallyInjective f, ∀ (K : Type u) [inst : Field K], Injective fun g ↦ g ≫ f,
      Injective ⇑f ∧ ∀ (x : ↥X), (CommRingCat.Hom.hom (Scheme.Hom.residueFieldMap f x)).IsPurelyInseparable,
      Surjective (pullback.diagonal f)].TFAE

Tactic:
tfae_have 1 ↔ 4 := UniversallyInjective.iff_diagonal f

Goal state after:
X Y : Scheme
f : X ⟶ Y
tfae_1_iff_4 : UniversallyInjective f ↔ Surjective (pullback.diagonal f)
⊢ [UniversallyInjective f, ∀ (K : Type u) [inst : Field K], Injective fun g ↦ g ≫ f,
      Injective ⇑f ∧ ∀ (x : ↥X), (CommRingCat.Hom.hom (Scheme.Hom.residueFieldMap f x)).IsPurelyInseparable,
      Surjective (pullback.diagonal f)].TFAE
Module: Mathlib.AlgebraicGeometry.Morphisms.UniversallyInjective

Goal state before:
pp: X Y : Scheme
f : X ⟶ Y
tfae_1_iff_4 : UniversallyInjective f ↔ Surjective (pullback.diagonal f)
tfae_3_to_2 :
  (Injective ⇑f ∧ ∀ (x : ↥X), (CommRingCat.Hom.hom (Scheme.Hom.residueFieldMap f x)).IsPurelyInseparable) →
    ∀ (K : Type u) [inst : Field K], Injective fun g ↦ g ≫ f
tfae_2_to_4 : (∀ (K : Type u) [inst : Field K], Injective fun g ↦ g ≫ f) → Surjective (pullback.diagonal f)
hf : Function.Surjective ⇑(pullback.diagonal f)
this : UniversallyInjective f
x : ↥X
algInst✝ : Algebra ↑(Y.residueField (f x)) ↑(X.residueField x) :=
  (CommRingCat.Hom.hom (Scheme.Hom.residueFieldMap f x)).toAlgebra
⊢ ∀ (x_1 y : Field.Emb ↑(Y.residueField (f x)) ↑(X.residueField x)), x_1 = y

Tactic:
intro σ₁

Goal state after:
X Y : Scheme
f : X ⟶ Y
tfae_1_iff_4 : UniversallyInjective f ↔ Surjective (pullback.diagonal f)
tfae_3_to_2 :
  (Injective ⇑f ∧ ∀ (x : ↥X), (CommRingCat.Hom.hom (Scheme.Hom.residueFieldMap f x)).IsPurelyInseparable) →
    ∀ (K : Type u) [inst : Field K], Injective fun g ↦ g ≫ f
tfae_2_to_4 : (∀ (K : Type u) [inst : Field K], Injective fun g ↦ g ≫ f) → Surjective (pullback.diagonal f)
hf : Function.Surjective ⇑(pullback.diagonal f)
this : UniversallyInjective f
x : ↥X
algInst✝ : Algebra ↑(Y.residueField (f x)) ↑(X.residueField x) :=
  (CommRingCat.Hom.hom (Scheme.Hom.residueFieldMap f x)).toAlgebra
σ₁ : Field.Emb ↑(Y.residueField (f x)) ↑(X.residueField x)
⊢ ∀ (y : Field.Emb ↑(Y.residueField (f x)) ↑(X.residueField x)), σ₁ = y
Module: Mathlib.AlgebraicGeometry.Cover.Directed

Goal state before:
pp: case refine_1
P : MorphismProperty Scheme
X : Scheme
𝒰 : X.OpenCover
inst✝ : Preorder 𝒰.I₀
hle : ∀ {i j : 𝒰.I₀}, i ≤ j ↔ Hom.opensRange (𝒰.f i) ≤ Hom.opensRange (𝒰.f j)
H : TopologicalSpace.Opens.IsBasis (Set.range fun i ↦ Hom.opensRange (𝒰.f i))
i j : 𝒰.I₀
x : ↥(pullback (𝒰.f i) (𝒰.f j))
this : (pullback.fst (𝒰.f i) (𝒰.f j) ≫ 𝒰.f i) x ∈ Hom.opensRange (pullback.fst (𝒰.f i) (𝒰.f j) ≫ 𝒰.f i)
k : 𝒰.I₀
h : (fun i ↦ Hom.opensRange (𝒰.f i)) k ≤ Hom.opensRange (pullback.fst (𝒰.f i) (𝒰.f j) ≫ 𝒰.f i)
y : ↥(𝒰.X k)
hy : (𝒰.f k) y = (pullback.fst (𝒰.f i) (𝒰.f j) ≫ 𝒰.f i) x
⊢ Hom.opensRange (pullback.fst (𝒰.f i) (𝒰.f j) ≫ 𝒰.f i) ≤ Hom.opensRange (𝒰.f i)

Tactic:
Scheme.Hom.opensRange_comp

Goal state after:
case refine_1
P : MorphismProperty Scheme
X : Scheme
𝒰 : X.OpenCover
inst✝ : Preorder 𝒰.I₀
hle : ∀ {i j : 𝒰.I₀}, i ≤ j ↔ Hom.opensRange (𝒰.f i) ≤ Hom.opensRange (𝒰.f j)
H : TopologicalSpace.Opens.IsBasis (Set.range fun i ↦ Hom.opensRange (𝒰.f i))
i j : 𝒰.I₀
x : ↥(pullback (𝒰.f i) (𝒰.f j))
this : (pullback.fst (𝒰.f i) (𝒰.f j) ≫ 𝒰.f i) x ∈ Hom.opensRange (pullback.fst (𝒰.f i) (𝒰.f j) ≫ 𝒰.f i)
k : 𝒰.I₀
h : (fun i ↦ Hom.opensRange (𝒰.f i)) k ≤ Hom.opensRange (pullback.fst (𝒰.f i) (𝒰.f j) ≫ 𝒰.f i)
y : ↥(𝒰.X k)
hy : (𝒰.f k) y = (pullback.fst (𝒰.f i) (𝒰.f j) ≫ 𝒰.f i) x
⊢ 𝒰.f i ''ᵁ Hom.opensRange (pullback.fst (𝒰.f i) (𝒰.f j)) ≤ Hom.opensRange (𝒰.f i)
Module: Mathlib.AlgebraicGeometry.Cover.Directed

Goal state before:
pp: case refine_2
P : MorphismProperty Scheme
X : Scheme
𝒰 : X.OpenCover
inst✝ : Preorder 𝒰.I₀
hle : ∀ {i j : 𝒰.I₀}, i ≤ j ↔ Hom.opensRange (𝒰.f i) ≤ Hom.opensRange (𝒰.f j)
H : TopologicalSpace.Opens.IsBasis (Set.range fun i ↦ Hom.opensRange (𝒰.f i))
i j : 𝒰.I₀
x : ↥(pullback (𝒰.f i) (𝒰.f j))
this : (pullback.fst (𝒰.f i) (𝒰.f j) ≫ 𝒰.f i) x ∈ Hom.opensRange (pullback.fst (𝒰.f i) (𝒰.f j) ≫ 𝒰.f i)
k : 𝒰.I₀
h : (fun i ↦ Hom.opensRange (𝒰.f i)) k ≤ Hom.opensRange (pullback.fst (𝒰.f i) (𝒰.f j) ≫ 𝒰.f i)
y : ↥(𝒰.X k)
hy : (𝒰.f k) y = (pullback.fst (𝒰.f i) (𝒰.f j) ≫ 𝒰.f i) x
⊢ Hom.opensRange (pullback.snd (𝒰.f i) (𝒰.f j) ≫ 𝒰.f j) ≤ Hom.opensRange (𝒰.f j)

Tactic:
Scheme.Hom.opensRange_comp

Goal state after:
case refine_2
P : MorphismProperty Scheme
X : Scheme
𝒰 : X.OpenCover
inst✝ : Preorder 𝒰.I₀
hle : ∀ {i j : 𝒰.I₀}, i ≤ j ↔ Hom.opensRange (𝒰.f i) ≤ Hom.opensRange (𝒰.f j)
H : TopologicalSpace.Opens.IsBasis (Set.range fun i ↦ Hom.opensRange (𝒰.f i))
i j : 𝒰.I₀
x : ↥(pullback (𝒰.f i) (𝒰.f j))
this : (pullback.fst (𝒰.f i) (𝒰.f j) ≫ 𝒰.f i) x ∈ Hom.opensRange (pullback.fst (𝒰.f i) (𝒰.f j) ≫ 𝒰.f i)
k : 𝒰.I₀
h : (fun i ↦ Hom.opensRange (𝒰.f i)) k ≤ Hom.opensRange (pullback.fst (𝒰.f i) (𝒰.f j) ≫ 𝒰.f i)
y : ↥(𝒰.X k)
hy : (𝒰.f k) y = (pullback.fst (𝒰.f i) (𝒰.f j) ≫ 𝒰.f i) x
⊢ 𝒰.f j ''ᵁ Hom.opensRange (pullback.snd (𝒰.f i) (𝒰.f j)) ≤ Hom.opensRange (𝒰.f j)
Module: Mathlib.AlgebraicGeometry.Cover.Over

Goal state before:
pp: case refine_1
P : MorphismProperty Scheme
S : Scheme
inst✝⁵ : P.IsStableUnderBaseChange
inst✝⁴ : IsJointlySurjectivePreserving P
X W : Scheme
𝒰 : Cover (precoverage P) X
f : W ⟶ X
inst✝³ : W.Over S
inst✝² : X.Over S
inst✝¹ : Cover.Over S 𝒰
inst✝ : Hom.IsOver f S
x : ↥W
⊢ ∃ i,
    x ∈
      Set.range
        ⇑({ I₀ := 𝒰.I₀, X := fun x ↦ (pullback (Hom.asOver (𝒰.f x) S) (Hom.asOver f S)).left,
                f := fun x ↦ Over.Hom.left (pullback.snd (Hom.asOver (𝒰.f x) S) (Hom.asOver f S)) }.f
            i)

pp: case refine_2
P : MorphismProperty Scheme
S : Scheme
inst✝⁵ : P.IsStableUnderBaseChange
inst✝⁴ : IsJointlySurjectivePreserving P
X W : Scheme
𝒰 : Cover (precoverage P) X
f : W ⟶ X
inst✝³ : W.Over S
inst✝² : X.Over S
inst✝¹ : Cover.Over S 𝒰
inst✝ : Hom.IsOver f S
j :
  { I₀ := 𝒰.I₀, X := fun x ↦ (pullback (Hom.asOver (𝒰.f x) S) (Hom.asOver f S)).left,
      f := fun x ↦ Over.Hom.left (pullback.snd (Hom.asOver (𝒰.f x) S) (Hom.asOver f S)) }.I₀
⊢ P
    ({ I₀ := 𝒰.I₀, X := fun x ↦ (pullback (Hom.asOver (𝒰.f x) S) (Hom.asOver f S)).left,
          f := fun x ↦ Over.Hom.left (pullback.snd (Hom.asOver (𝒰.f x) S) (Hom.asOver f S)) }.f
      j)

Tactic:
· obtain ⟨i, hy⟩ := Cover.exists_eq (𝒰.pullback₂ f) x
      use i
      exact (mem_range_iff_of_surjective ((𝒰.pullback₂ f).f _) _
        ((PreservesPullback.iso (Over.forget S) ((𝒰.f _).asOver S) (f.asOver S)).inv)
        (PreservesPullback.iso_inv_snd _ _ _) x).mp hy

Goal state after:
case refine_2
P : MorphismProperty Scheme
S : Scheme
inst✝⁵ : P.IsStableUnderBaseChange
inst✝⁴ : IsJointlySurjectivePreserving P
X W : Scheme
𝒰 : Cover (precoverage P) X
f : W ⟶ X
inst✝³ : W.Over S
inst✝² : X.Over S
inst✝¹ : Cover.Over S 𝒰
inst✝ : Hom.IsOver f S
j :
  { I₀ := 𝒰.I₀, X := fun x ↦ (pullback (Hom.asOver (𝒰.f x) S) (Hom.asOver f S)).left,
      f := fun x ↦ Over.Hom.left (pullback.snd (Hom.asOver (𝒰.f x) S) (Hom.asOver f S)) }.I₀
⊢ P
    ({ I₀ := 𝒰.I₀, X := fun x ↦ (pullback (Hom.asOver (𝒰.f x) S) (Hom.asOver f S)).left,
          f := fun x ↦ Over.Hom.left (pullback.snd (Hom.asOver (𝒰.f x) S) (Hom.asOver f S)) }.f
      j)