mathlib-initiative/mathlib-tactics huggingface dataset:
Module: Mathlib.RingTheory.Unramified.LocalStructure

Goal state before:
pp: R : Type u_1
S : Type u_3
inst✝⁸ : CommRing R
inst✝⁷ : CommRing S
inst✝⁶ : Algebra R S
P : Ideal R
inst✝⁵ : P.IsPrime
Q : Ideal S
inst✝⁴ : Q.IsPrime
inst✝³ : Q.LiesOver P
inst✝² : IsUnramifiedAt R Q
x : S
p : R[X]
inst✝¹ : Algebra (Localization.AtPrime P) (Localization.AtPrime Q)
inst✝ : Localization.AtPrime.IsLiesOverAlgebra P Q
hp₁ : Ideal.span {Polynomial.map (algebraMap R P.ResidueField) p} = RingHom.ker (aeval (1 ⊗ₜ[R] x)).toRingHom
hp₂ : R[x] = ⊤
Q' : Ideal (P.Fiber S) := ((PrimeSpectrum.primesOverOrderIsoFiber R S P) ⟨Q, ⋯⟩).asIdeal
this✝³ : Q'.LiesOver Q
this✝² : Q'.LiesOver P
this✝¹ : Algebra (Localization.AtPrime Q) (Localization.AtPrime Q') := Localization.AtPrime.algebraOfLiesOver Q Q'
this✝ : Algebra (Localization.AtPrime P) (Localization.AtPrime Q') := Localization.AtPrime.algebraOfLiesOver P Q'
this : IsUnramifiedAt P.ResidueField Q'
⊢ Function.Surjective ⇑(aeval (1 ⊗ₜ[R] x))

Tactic:
← AlgHom.range_eq_top,

Goal state after:
R : Type u_1
S : Type u_3
inst✝⁸ : CommRing R
inst✝⁷ : CommRing S
inst✝⁶ : Algebra R S
P : Ideal R
inst✝⁵ : P.IsPrime
Q : Ideal S
inst✝⁴ : Q.IsPrime
inst✝³ : Q.LiesOver P
inst✝² : IsUnramifiedAt R Q
x : S
p : R[X]
inst✝¹ : Algebra (Localization.AtPrime P) (Localization.AtPrime Q)
inst✝ : Localization.AtPrime.IsLiesOverAlgebra P Q
hp₁ : Ideal.span {Polynomial.map (algebraMap R P.ResidueField) p} = RingHom.ker (aeval (1 ⊗ₜ[R] x)).toRingHom
hp₂ : R[x] = ⊤
Q' : Ideal (P.Fiber S) := ((PrimeSpectrum.primesOverOrderIsoFiber R S P) ⟨Q, ⋯⟩).asIdeal
this✝³ : Q'.LiesOver Q
this✝² : Q'.LiesOver P
this✝¹ : Algebra (Localization.AtPrime Q) (Localization.AtPrime Q') := Localization.AtPrime.algebraOfLiesOver Q Q'
this✝ : Algebra (Localization.AtPrime P) (Localization.AtPrime Q') := Localization.AtPrime.algebraOfLiesOver P Q'
this : IsUnramifiedAt P.ResidueField Q'
⊢ (aeval (1 ⊗ₜ[R] x)).range = ⊤
Module: Mathlib.RingTheory.Smooth.IntegralClosure

Goal state before:
pp: case refine_1
R : Type u_1
S : Type u_2
B : Type u_3
inst✝⁴ : CommRing R
inst✝³ : CommRing S
inst✝² : Algebra R S
inst✝¹ : CommRing B
inst✝ : Algebra R B
φ : S[X] →ₐ[R] B
hφ : Function.Surjective ⇑φ
f : S[X]
hf : f.Monic
hf' : ∀ (i : ℕ), IsIntegral R (f.coeff i)
hfx : RingHom.ker φ.toRingHom = Ideal.span {f}
h✝ : Nontrivial B
hfd : f.natDegree ≠ 0
algInst✝¹ : Algebra S B := (φ.comp C).toAlgebra
this : Nontrivial S
y : S[X]
hy : IsIntegral R (φ y)
S' : Type u_2
w✝⁴ : CommRing S'
w✝³ : Algebra S S'
w✝² : Module.Finite S S'
w✝¹ : Module.Free S S'
w✝ : Nontrivial S'
hS' : (Polynomial.map (algebraMap S S') f).Splits
m : Multiset S'
hm : Polynomial.map (algebraMap S S') f = (Multiset.map (fun x ↦ X - C x) m).prod
algInst✝ : Algebra R S' := ((algebraMap S S').comp (algebraMap R S)).toAlgebra
scalarTowerInst✝ : IsScalarTower R S S' := IsScalarTower.of_algebraMap_eq' (Eq.refl (algebraMap R S'))
a : S'
ham : a ∈ m
⊢ (Polynomial.map (algebraMap S S') f).natDegree ≠ 0

Tactic:
rwa [hf.natDegree_map]

Goal state after:
Module: Mathlib.RingTheory.Unramified.LocalStructure

Goal state before:
pp: case refine_2
R : Type u_1
S : Type u_3
inst✝⁵ : CommRing R
inst✝⁴ : CommRing S
inst✝³ : Algebra R S
Q : Ideal S
inst✝² : Q.IsPrime
inst✝¹ : Module.Finite R S
inst✝ : IsUnramifiedAt R Q
this✝¹ : Algebra (Localization.AtPrime (Ideal.under R Q)) (Localization.AtPrime Q) :=
  Localization.AtPrime.algebraOfLiesOver (Ideal.under R Q) Q
t : S
htQ : t ∉ Q
htQ' : ∀ Q' ∈ (Ideal.under R Q).primesOver S, Q' ≠ Q → t ∈ Q'
ht : (Ideal.under R Q).ResidueField[(algebraMap S Q.ResidueField) t] = ⊤
p : Ideal R := Ideal.under R Q
this✝ : Algebra (Localization.AtPrime p) (Localization.AtPrime (Ideal.under (↥R[t]) Q)) :=
  Localization.AtPrime.algebraOfLiesOver p (Ideal.under (↥R[t]) Q)
this : Algebra (Localization.AtPrime (Ideal.under (↥R[t]) Q)) (Localization.AtPrime Q) :=
  Localization.AtPrime.algebraOfLiesOver (Ideal.under (↥R[t]) Q) Q
⊢ Function.Surjective ⇑(IsScalarTower.toAlgHom p.ResidueField (Ideal.under (↥R[t]) Q).ResidueField Q.ResidueField)

Tactic:
← AlgHom.range_eq_top,

Goal state after:
case refine_2
R : Type u_1
S : Type u_3
inst✝⁵ : CommRing R
inst✝⁴ : CommRing S
inst✝³ : Algebra R S
Q : Ideal S
inst✝² : Q.IsPrime
inst✝¹ : Module.Finite R S
inst✝ : IsUnramifiedAt R Q
this✝¹ : Algebra (Localization.AtPrime (Ideal.under R Q)) (Localization.AtPrime Q) :=
  Localization.AtPrime.algebraOfLiesOver (Ideal.under R Q) Q
t : S
htQ : t ∉ Q
htQ' : ∀ Q' ∈ (Ideal.under R Q).primesOver S, Q' ≠ Q → t ∈ Q'
ht : (Ideal.under R Q).ResidueField[(algebraMap S Q.ResidueField) t] = ⊤
p : Ideal R := Ideal.under R Q
this✝ : Algebra (Localization.AtPrime p) (Localization.AtPrime (Ideal.under (↥R[t]) Q)) :=
  Localization.AtPrime.algebraOfLiesOver p (Ideal.under (↥R[t]) Q)
this : Algebra (Localization.AtPrime (Ideal.under (↥R[t]) Q)) (Localization.AtPrime Q) :=
  Localization.AtPrime.algebraOfLiesOver (Ideal.under (↥R[t]) Q) Q
⊢ (IsScalarTower.toAlgHom p.ResidueField (Ideal.under (↥R[t]) Q).ResidueField Q.ResidueField).range = ⊤
Module: Mathlib.RingTheory.ZariskisMainTheorem

Goal state before:
pp: case inr.h.succ.inr
R : Type u_1
S : Type u_2
inst✝² : CommRing R
inst✝¹ : CommRing S
inst✝ : Algebra R S
φ : R[X] →ₐ[R] S
t : S
hRS : integralClosure R S = ⊥
hφ : φ.Finite
i : ℕ
this : ∀ (p : R[X]), φ p * t ∈ (conductor R (φ X)).radical → p.leadingCoeff • t ∈ (conductor R (φ X)).radical
p : R[X]
hp : φ p * t ∈ (conductor R (φ X)).radical
n : ℕ
IH :
  ∀ m < n + 1,
    ∀ (p : R[X]), φ p * t ∈ (conductor R (φ X)).radical → p.natDegree = m → p.coeff i • t ∈ (conductor R (φ X)).radical
hpn : p.natDegree = n + 1
hi' : i ≠ p.natDegree
⊢ p.coeff i • t ∈ (conductor R (φ X)).radical

Tactic:
have : φ p.eraseLead * t ∈ (conductor R (φ X)).radical := by
        simp only [← self_sub_C_mul_X_pow, map_sub, ← algebraMap_eq, map_mul, AlgHom.commutes,
          map_pow, sub_mul, mul_right_comm _ _ t, ← Algebra.smul_def _ t]
        exact sub_mem hp (Ideal.mul_mem_right _ _ (this _ hp))

Goal state after:
case inr.h.succ.inr
R : Type u_1
S : Type u_2
inst✝² : CommRing R
inst✝¹ : CommRing S
inst✝ : Algebra R S
φ : R[X] →ₐ[R] S
t : S
hRS : integralClosure R S = ⊥
hφ : φ.Finite
i : ℕ
this✝ : ∀ (p : R[X]), φ p * t ∈ (conductor R (φ X)).radical → p.leadingCoeff • t ∈ (conductor R (φ X)).radical
p : R[X]
hp : φ p * t ∈ (conductor R (φ X)).radical
n : ℕ
IH :
  ∀ m < n + 1,
    ∀ (p : R[X]), φ p * t ∈ (conductor R (φ X)).radical → p.natDegree = m → p.coeff i • t ∈ (conductor R (φ X)).radical
hpn : p.natDegree = n + 1
hi' : i ≠ p.natDegree
this : φ p.eraseLead * t ∈ (conductor R (φ X)).radical
⊢ p.coeff i • t ∈ (conductor R (φ X)).radical
Module: Mathlib.RingTheory.ZariskisMainTheorem

Goal state before:
pp: R : Type u_1
S : Type u_2
inst✝⁷ : CommRing R
inst✝⁶ : CommRing S
inst✝⁵ : Algebra R S
inst✝⁴ : FaithfulSMul R S
inst✝³ : IsIntegrallyClosed R
inst✝² : IsDomain S
P : Ideal S
inst✝¹ : P.IsPrime
inst✝ : WeaklyQuasiFiniteAt R P
this✝⁴ : IsDomain R
f : R[X] →ₐ[R] S
hx' : f.Finite
hf' : Function.Injective ⇑f
hx : IsStronglyTranscendental R (f X)
hf : aeval (f X) = f
this✝³ : Algebra R[X] S := f.toAlgebra
this✝² : IsScalarTower R R[X] S
this✝¹ : Module.Finite R[X] S
this✝ : FaithfulSMul R[X] S
this : Ideal.map C (Ideal.under R P) < Ideal.under R[X] P
Q : Ideal S
hQ : Q < P
left✝ : Q.IsPrime
e : Ideal.map C (Ideal.under R P) = Ideal.under R[X] Q
⊢ False

Tactic:
refine hQ.ne (Algebra.WeaklyQuasiFiniteAt.eq_of_le_of_under_eq (R := R) hQ.le ?_)

Goal state after:
R : Type u_1
S : Type u_2
inst✝⁷ : CommRing R
inst✝⁶ : CommRing S
inst✝⁵ : Algebra R S
inst✝⁴ : FaithfulSMul R S
inst✝³ : IsIntegrallyClosed R
inst✝² : IsDomain S
P : Ideal S
inst✝¹ : P.IsPrime
inst✝ : WeaklyQuasiFiniteAt R P
this✝⁴ : IsDomain R
f : R[X] →ₐ[R] S
hx' : f.Finite
hf' : Function.Injective ⇑f
hx : IsStronglyTranscendental R (f X)
hf : aeval (f X) = f
this✝³ : Algebra R[X] S := f.toAlgebra
this✝² : IsScalarTower R R[X] S
this✝¹ : Module.Finite R[X] S
this✝ : FaithfulSMul R[X] S
this : Ideal.map C (Ideal.under R P) < Ideal.under R[X] P
Q : Ideal S
hQ : Q < P
left✝ : Q.IsPrime
e : Ideal.map C (Ideal.under R P) = Ideal.under R[X] Q
⊢ Ideal.under R Q = Ideal.under R P
Module: Mathlib.RingTheory.ZariskisMainTheorem

Goal state before:
pp: R : Type u_1
S : Type u_2
inst✝⁵ : CommRing R
inst✝⁴ : CommRing S
inst✝³ : Algebra R S
inst✝² : IsReduced S
x : S
hx' : (aeval x).Finite
P : Ideal S
inst✝¹ : P.IsPrime
inst✝ : WeaklyQuasiFiniteAt R P
left✝ : IsDomain S
right✝ : FaithfulSMul R S
this✝ : IsDomain R
K : Type u_1 := FractionRing R
L : Type u_2 := FractionRing S
this : Algebra K L := FractionRing.liftAlgebra R L
R' : Subalgebra R K := integralClosure R K
S' : Subalgebra (↥R') L := adjoin ↥R' ↑(algebraMap S L).range
f : S →ₐ[R] ↥S' := (IsScalarTower.toAlgHom R S L).codRestrict (Subalgebra.restrictScalars R S') ⋯
g : ↥R' ⊗[R] S →ₐ[↥R'] ↥S' := TensorProduct.lift (ofId ↥R' ↥S') f ⋯
⊢ Function.Surjective ⇑g

Tactic:
← AlgHom.range_eq_top,

Goal state after:
R : Type u_1
S : Type u_2
inst✝⁵ : CommRing R
inst✝⁴ : CommRing S
inst✝³ : Algebra R S
inst✝² : IsReduced S
x : S
hx' : (aeval x).Finite
P : Ideal S
inst✝¹ : P.IsPrime
inst✝ : WeaklyQuasiFiniteAt R P
left✝ : IsDomain S
right✝ : FaithfulSMul R S
this✝ : IsDomain R
K : Type u_1 := FractionRing R
L : Type u_2 := FractionRing S
this : Algebra K L := FractionRing.liftAlgebra R L
R' : Subalgebra R K := integralClosure R K
S' : Subalgebra (↥R') L := adjoin ↥R' ↑(algebraMap S L).range
f : S →ₐ[R] ↥S' := (IsScalarTower.toAlgHom R S L).codRestrict (Subalgebra.restrictScalars R S') ⋯
g : ↥R' ⊗[R] S →ₐ[↥R'] ↥S' := TensorProduct.lift (ofId ↥R' ↥S') f ⋯
⊢ g.range = ⊤
Module: Mathlib.RingTheory.ZariskisMainTheorem

Goal state before:
pp: R✝ S✝ : Type u
inst✝⁷ : CommRing R✝
inst✝⁶ : CommRing S✝
inst✝⁵ : Algebra R✝ S✝
R S : Type u
inst✝⁴ : CommRing R
inst✝³ : CommRing S
inst✝² : Algebra R S
p : Ideal S
inst✝¹ : p.IsPrime
inst✝ : WeaklyQuasiFiniteAt R p
x : S
hx : R[x] = ⊤
H : integralClosure R S = ⊥
⊢ Function.Surjective ⇑(aeval x)

Tactic:
← AlgHom.range_eq_top,

Goal state after:
R✝ S✝ : Type u
inst✝⁷ : CommRing R✝
inst✝⁶ : CommRing S✝
inst✝⁵ : Algebra R✝ S✝
R S : Type u
inst✝⁴ : CommRing R
inst✝³ : CommRing S
inst✝² : Algebra R S
p : Ideal S
inst✝¹ : p.IsPrime
inst✝ : WeaklyQuasiFiniteAt R p
x : S
hx : R[x] = ⊤
H : integralClosure R S = ⊥
⊢ (aeval x).range = ⊤
Module: Mathlib.RingTheory.Polynomial.Resultant.Basic

Goal state before:
pp: case zero
R : Type u_1
inst✝ : CommRing R
f g : R[X]
m : ℕ
hf : f.natDegree ≤ m
⊢ f.resultant g (m + 1) 0 = (-1) ^ 0 * g.coeff 0 * f.resultant g m 0

Tactic:
simp [pow_succ']

Goal state after:
Module: Mathlib.RingTheory.Polynomial.Resultant.Basic

Goal state before:
pp: R : Type u_1
inst✝ : CommRing R
f : R[X]
m n : ℕ
⊢ f.resultant 1 m n = f.coeff m ^ n

Tactic:
by
  simpa [-resultant_C_right] using! resultant_C_right f m n 1

Goal state after:
Module: Mathlib.RingTheory.Polynomial.Resultant.Basic

Goal state before:
pp: case neg
n : ℕ
IH :
  ∀ m < n,
    ∀ {K : Type u_3} [inst : Field K] (f g : K[X]),
      f.Monic →
        g.Monic →
          f.Splits →
            g.Splits →
              g.natDegree ≤ f.natDegree →
                f.natDegree + g.natDegree = m →
                  f.resultant g = (Multiset.map (fun ij ↦ ij.1 - ij.2) (f.roots ×ˢ g.roots)).prod
K : Type u_3
inst✝ : Field K
g : K[X]
hg : g.Monic
hg' : g.Splits
r : K[X]
hf : (g * r).Monic
hf' : (g * r).Splits
hfg : g.natDegree ≤ (g * r).natDegree
hN : (g * r).natDegree + g.natDegree = n
hr' : r ≠ 0
H : ¬g.natDegree = 0
⊢ 0 * g.coeff 0 ^ (g * r).natDegree = (Multiset.map (fun ij ↦ ij.1 - ij.2) ((g * r).roots ×ˢ g.roots)).prod

Tactic:
hg'.natDegree_eq_card_roots,

Goal state after:
case neg
n : ℕ
IH :
  ∀ m < n,
    ∀ {K : Type u_3} [inst : Field K] (f g : K[X]),
      f.Monic →
        g.Monic →
          f.Splits →
            g.Splits →
              g.natDegree ≤ f.natDegree →
                f.natDegree + g.natDegree = m →
                  f.resultant g = (Multiset.map (fun ij ↦ ij.1 - ij.2) (f.roots ×ˢ g.roots)).prod
K : Type u_3
inst✝ : Field K
g : K[X]
hg : g.Monic
hg' : g.Splits
r : K[X]
hf : (g * r).Monic
hf' : (g * r).Splits
hfg : g.natDegree ≤ (g * r).natDegree
hN : (g * r).natDegree + g.natDegree = n
hr' : r ≠ 0
H : ¬g.roots.card = 0
⊢ 0 * g.coeff 0 ^ (g * r).natDegree = (Multiset.map (fun ij ↦ ij.1 - ij.2) ((g * r).roots ×ˢ g.roots)).prod
Module: Mathlib.RingTheory.Ideal.Quotient.Over

Goal state before:
pp: R : Type u_1
S : Type u_2
T : Type u_3
inst✝⁶ : CommRing R
inst✝⁵ : CommRing S
inst✝⁴ : CommRing T
inst✝³ : Algebra R S
inst✝² : Algebra R T
f : S →ₐ[R] T
Hf : Function.Surjective ⇑f
P : Ideal R
P' : Ideal S
inst✝¹ : P'.IsPrime
inst✝ : P'.LiesOver P
hkP' : ¬RingHom.ker f.toRingHom ≤ P'
H : (P.primesOver S).Finite
⊢ (P.primesOver T).ncard < (P.primesOver S).ncard

Tactic:
rw [← Set.ncard_image_of_injective _ (Ideal.comap_injective_of_surjective _ Hf)]

Goal state after:
R : Type u_1
S : Type u_2
T : Type u_3
inst✝⁶ : CommRing R
inst✝⁵ : CommRing S
inst✝⁴ : CommRing T
inst✝³ : Algebra R S
inst✝² : Algebra R T
f : S →ₐ[R] T
Hf : Function.Surjective ⇑f
P : Ideal R
P' : Ideal S
inst✝¹ : P'.IsPrime
inst✝ : P'.LiesOver P
hkP' : ¬RingHom.ker f.toRingHom ≤ P'
H : (P.primesOver S).Finite
⊢ (comap f '' P.primesOver T).ncard < (P.primesOver S).ncard
Module: Mathlib.AlgebraicGeometry.Normalization

Goal state before:
pp: case e_a
X Y : Scheme
f : X ⟶ Y
inst✝² : QuasiCompact f
inst✝¹ : QuasiSeparated f
T : Scheme
f₁ : X ⟶ T
f₂ : T ⟶ Y
inst✝ : IsIntegralHom f₂
H : f = f₁ ≫ f₂
U : (directedCover Y).I₀
i : ↑Γ(Y, ↑U)
⊢ (CommRingCat.Hom.hom (appLE f₁ (f₂ ⁻¹ᵁ ↑U) (f ⁻¹ᵁ toOpens U) ⋯))
      ((CommRingCat.Hom.hom (appLE f₂ (↑U) (f₂ ⁻¹ᵁ ↑U) ⋯)) i) =
    (CommRingCat.Hom.hom (app f (toOpens U))) i

Tactic:
← CommRingCat.comp_apply,

Goal state after:
case e_a
X Y : Scheme
f : X ⟶ Y
inst✝² : QuasiCompact f
inst✝¹ : QuasiSeparated f
T : Scheme
f₁ : X ⟶ T
f₂ : T ⟶ Y
inst✝ : IsIntegralHom f₂
H : f = f₁ ≫ f₂
U : (directedCover Y).I₀
i : ↑Γ(Y, ↑U)
⊢ (ConcreteCategory.hom (appLE f₂ (↑U) (f₂ ⁻¹ᵁ ↑U) ⋯ ≫ appLE f₁ (f₂ ⁻¹ᵁ ↑U) (f ⁻¹ᵁ toOpens U) ⋯)) i =
    (CommRingCat.Hom.hom (app f (toOpens U))) i
Module: Mathlib.RingTheory.Polynomial.Resultant.Basic

Goal state before:
pp: case inr
R : Type u_1
inst✝ : CommRing R
f g₁ g₂ : R[X]
this :
  ∀ {R : Type u_1} [inst : CommRing R] (f g₁ g₂ : R[X]) (m : ℕ),
    f.natDegree ≤ m →
      m = f.natDegree → f.resultant (g₁ * g₂) m (g₁.natDegree + g₂.natDegree) = f.resultant g₁ m * f.resultant g₂ m
c : ℕ
hm : f.natDegree ≤ f.natDegree + c
hgn : ¬f.natDegree + c = f.natDegree
⊢ f.resultant (g₁ * g₂) (f.natDegree + c) (g₁.natDegree + g₂.natDegree) =
    f.resultant g₁ (f.natDegree + c) * f.resultant g₂ (f.natDegree + c)

Tactic:
simp [resultant_add_left_deg, this f g₁ g₂, coeff_mul_degree_add_degree]

Goal state after:
case inr
R : Type u_1
inst✝ : CommRing R
f g₁ g₂ : R[X]
this :
  ∀ {R : Type u_1} [inst : CommRing R] (f g₁ g₂ : R[X]) (m : ℕ),
    f.natDegree ≤ m →
      m = f.natDegree → f.resultant (g₁ * g₂) m (g₁.natDegree + g₂.natDegree) = f.resultant g₁ m * f.resultant g₂ m
c : ℕ
hm : f.natDegree ≤ f.natDegree + c
hgn : ¬f.natDegree + c = f.natDegree
⊢ (-1) ^ ((g₁.natDegree + g₂.natDegree) * c) * (g₁.leadingCoeff * g₂.leadingCoeff) ^ c *
      (f.resultant g₁ * f.resultant g₂) =
    (-1) ^ (g₁.natDegree * c) * g₁.leadingCoeff ^ c * f.resultant g₁ *
      ((-1) ^ (g₂.natDegree * c) * g₂.leadingCoeff ^ c * f.resultant g₂)
Module: Mathlib.RingTheory.Polynomial.Resultant.Basic

Goal state before:
pp: case pos
R✝ : Type u_1
inst✝¹ : CommRing R✝
R : Type u_1
inst✝ : Field R
f : R[X]
hf : f.Splits
h : f.natDegree = 0
⊢ f.resultant f = 0 ^ f.natDegree

Tactic:
obtain ⟨r, rfl⟩ := natDegree_eq_zero.mp h

Goal state after:
case pos
R✝ : Type u_1
inst✝¹ : CommRing R✝
R : Type u_1
inst✝ : Field R
r : R
hf : (C r).Splits
h : (C r).natDegree = 0
⊢ (C r).resultant (C r) = 0 ^ (C r).natDegree
Module: Mathlib.RingTheory.Polynomial.Resultant.Basic

Goal state before:
pp: case neg.inr
R✝ : Type u_1
inst✝¹ : CommRing R✝
R : Type u_1
inst✝ : Field R
f : R[X]
hf' : f.Splits
g : R[X]
r : R
hf : f ≠ 0
hg : g ≠ 0
hf0 : ¬f.natDegree = 0
hg0 : ¬g.natDegree = 0
hr : r ≠ 0
⊢ (f.scaleRoots r).leadingCoeff ^ (g.scaleRoots r).natDegree *
      (Multiset.map (fun x ↦ eval x (g.scaleRoots r)) (f.scaleRoots r).roots).prod =
    r ^ (f.natDegree * g.natDegree) * (f.leadingCoeff ^ g.natDegree * (Multiset.map (fun x ↦ eval x g) f.roots).prod)

Tactic:
roots_scaleRoots _ (isUnit_iff_ne_zero.mpr hr)

Goal state after:
case neg.inr
R✝ : Type u_1
inst✝¹ : CommRing R✝
R : Type u_1
inst✝ : Field R
f : R[X]
hf' : f.Splits
g : R[X]
r : R
hf : f ≠ 0
hg : g ≠ 0
hf0 : ¬f.natDegree = 0
hg0 : ¬g.natDegree = 0
hr : r ≠ 0
⊢ (f.scaleRoots r).leadingCoeff ^ (g.scaleRoots r).natDegree *
      (Multiset.map (fun x ↦ eval x (g.scaleRoots r)) (Multiset.map (fun x ↦ r * x) f.roots)).prod =
    r ^ (f.natDegree * g.natDegree) * (f.leadingCoeff ^ g.natDegree * (Multiset.map (fun x ↦ eval x g) f.roots).prod)
Module: Mathlib.RingTheory.Polynomial.Resultant.Basic

Goal state before:
pp: case neg.refine_2
R : Type u_1
inst✝ : CommRing R
f g : R[X]
hf : f.Monic
hf0 : ¬f.natDegree = 0
⊢ IsCoprime f g → IsUnit (f.resultant g)

Tactic:
intro ⟨a, b, e⟩

Goal state after:
case neg.refine_2
R : Type u_1
inst✝ : CommRing R
f g : R[X]
hf : f.Monic
hf0 : ¬f.natDegree = 0
a b : R[X]
e : a * f + b * g = 1
⊢ IsUnit (f.resultant g)
Module: Mathlib.CategoryTheory.Monoidal.Cartesian.Grp

Goal state before:
pp: case succ
C : Type u
inst✝³ : Category.{v, u} C
inst✝² : CartesianMonoidalCategory C
inst✝¹ : BraidedCategory C
G H : Grp C
inst✝ : IsCommMonObj H.X
f : G ⟶ H
n : ℕ
hn : (f ^ n).hom = f.hom ^ n
⊢ (f ^ (n + 1)).hom = f.hom ^ (n + 1)

Tactic:
simp [pow_succ, hn]

Goal state after:
Module: Mathlib.RingTheory.Finiteness.Descent

Goal state before:
pp: R : Type u_1
S : Type u_2
inst✝⁶ : CommRing R
inst✝⁵ : CommRing S
inst✝⁴ : Algebra R S
T : Type u_3
inst✝³ : CommRing T
inst✝² : Algebra R T
inst✝¹ : Module.FaithfullyFlat R T
inst✝ : FiniteType T (T ⊗[R] S)
s : Finset (T ⊗[R] S)
hs : adjoin T ↑s = ⊤
k : ↥s → ℕ
t : (x : ↥s) → Fin (k x) → T
m : (x : ↥s) → Fin (k x) → S
h : ∀ (x : ↥s), ↑x = ∑ j, t x j ⊗ₜ[R] m x j
f : MvPolynomial ((x : ↥s) × Fin (k x)) R →ₐ[R] S :=
  MvPolynomial.aeval fun x ↦
    match x with
    | ⟨x, i⟩ => m x i
⊢ Function.Surjective ⇑(TensorProduct.map (AlgHom.id T T) f)

Tactic:
← AlgHom.range_eq_top,

Goal state after:
R : Type u_1
S : Type u_2
inst✝⁶ : CommRing R
inst✝⁵ : CommRing S
inst✝⁴ : Algebra R S
T : Type u_3
inst✝³ : CommRing T
inst✝² : Algebra R T
inst✝¹ : Module.FaithfullyFlat R T
inst✝ : FiniteType T (T ⊗[R] S)
s : Finset (T ⊗[R] S)
hs : adjoin T ↑s = ⊤
k : ↥s → ℕ
t : (x : ↥s) → Fin (k x) → T
m : (x : ↥s) → Fin (k x) → S
h : ∀ (x : ↥s), ↑x = ∑ j, t x j ⊗ₜ[R] m x j
f : MvPolynomial ((x : ↥s) × Fin (k x)) R →ₐ[R] S :=
  MvPolynomial.aeval fun x ↦
    match x with
    | ⟨x, i⟩ => m x i
⊢ (TensorProduct.map (AlgHom.id T T) f).range = ⊤
Module: Mathlib.RingTheory.Extension.Cotangent.BaseChange

Goal state before:
pp: R : Type u_1
S : Type u_2
inst✝⁴ : CommRing R
inst✝³ : CommRing S
inst✝² : Algebra R S
P : Extension R S
T : Type u_3
inst✝¹ : CommRing T
inst✝ : Algebra R T
t : T
s : S
x : Ω[P.Ring⁄R]
this : x ∈ Submodule.span P.Ring (Set.range ⇑(KaehlerDifferential.D R P.Ring))
⊢ t ⊗ₜ[R] s ⊗ₜ[P.baseChange.Ring]
      (KaehlerDifferential.tensorKaehlerEquiv R T P.Ring P.baseChange.Ring) (1 ⊗ₜ[P.Ring] x) =
    t ⊗ₜ[R] s ⊗ₜ[P.baseChange.Ring] (KaehlerDifferential.map R T P.Ring P.baseChange.Ring) x

Tactic:
induction this using Submodule.span_induction with

Goal state after:
Module: Mathlib.RingTheory.Extension.Cotangent.BaseChange

Goal state before:
pp: case zero
R : Type u_1
S : Type u_2
inst✝⁴ : CommRing R
inst✝³ : CommRing S
inst✝² : Algebra R S
P : Extension R S
T : Type u_3
inst✝¹ : CommRing T
inst✝ : Algebra R T
t : T
⊢ (P.tensorCotangentSpace T) (t ⊗ₜ[R] 0) = t • (CotangentSpace.map (toBaseChange T)) 0

Tactic:
rw [tmul_zero, LinearEquiv.map_zero, LinearMap.map_zero, smul_zero]

Goal state after:
Module: Mathlib.RingTheory.KrullDimension.NonZeroDivisors

Goal state before:
pp: case inr
R : Type u_1
inst✝ : CommRing R
σ : Type u_3
a✝ : Nontrivial R
h✝ : Infinite σ
n : ℕ
⊢ ↑n ≤ ringKrullDim (MvPolynomial σ R)

Tactic:
let ι := Infinite.natEmbedding σ ∘ Fin.val (n := n + 1)

Goal state after:
case inr
R : Type u_1
inst✝ : CommRing R
σ : Type u_3
a✝ : Nontrivial R
h✝ : Infinite σ
n : ℕ
ι : Fin (n + 1) → σ := ⇑(Infinite.natEmbedding σ) ∘ Fin.val
⊢ ↑n ≤ ringKrullDim (MvPolynomial σ R)
Module: Mathlib.AlgebraicGeometry.ProjectiveSpectrum.Topology

Goal state before:
pp: A : Type u_1
σ : Type u_2
inst✝³ : CommRing A
inst✝² : SetLike σ A
inst✝¹ : AddSubmonoidClass σ A
𝒜 : ℕ → σ
inst✝ : GradedRing 𝒜
⊢ ∀ A_1 ∈ Set.range (zeroLocus 𝒜), ∀ B ∈ Set.range (zeroLocus 𝒜), A_1 ∪ B ∈ Set.range (zeroLocus 𝒜)

Tactic:
rintro _ ⟨s, rfl⟩ _ ⟨t, rfl⟩
      exact ⟨_, (union_zeroLocus 𝒜 s t).symm⟩

Goal state after:
Module: Mathlib.AlgebraicGeometry.ProjectiveSpectrum.Topology

Goal state before:
pp: A : Type u_1
σ : Type u_2
inst✝³ : CommRing A
inst✝² : SetLike σ A
inst✝¹ : AddSubmonoidClass σ A
𝒜 : ℕ → σ
inst✝ : GradedRing 𝒜
f : A
z : ProjectiveSpectrum 𝒜
⊢ z ∈ ↑(basicOpen 𝒜 f) ↔ z ∈ ↑(⨆ i, basicOpen 𝒜 ((GradedRing.proj 𝒜 i) f))

Tactic:
mem_coe_basicOpen,

Goal state after:
A : Type u_1
σ : Type u_2
inst✝³ : CommRing A
inst✝² : SetLike σ A
inst✝¹ : AddSubmonoidClass σ A
𝒜 : ℕ → σ
inst✝ : GradedRing 𝒜
f : A
z : ProjectiveSpectrum 𝒜
⊢ f ∉ z.asHomogeneousIdeal ↔ z ∈ ↑(⨆ i, basicOpen 𝒜 ((GradedRing.proj 𝒜 i) f))
Module: Mathlib.RingTheory.GradedAlgebra.FiniteType

Goal state before:
pp: S : Type u_1
σ : Type u_2
ι : Type u_3
inst✝⁶ : DecidableEq ι
inst✝⁵ : AddCommMonoid ι
inst✝⁴ : CommRing S
inst✝³ : SetLike σ S
inst✝² : AddSubgroupClass σ S
𝒜 : ι → σ
inst✝¹ : GradedRing 𝒜
inst✝ : Algebra.FiniteType (↥(𝒜 0)) S
s : Finset S
h₁ : Algebra.adjoin ↥(𝒜 0) ↑s = ⊤
h₂ : ∀ i ∈ s, SetLike.IsHomogeneousElem 𝒜 i
⊢ ∃ s, Algebra.adjoin ↥(𝒜 0) ↑s = ⊤ ∧ ∀ i ∈ s, ∃ n, n ≠ 0 ∧ i ∈ 𝒜 n

Tactic:
choose! n hn using h₂

Goal state after:
S : Type u_1
σ : Type u_2
ι : Type u_3
inst✝⁶ : DecidableEq ι
inst✝⁵ : AddCommMonoid ι
inst✝⁴ : CommRing S
inst✝³ : SetLike σ S
inst✝² : AddSubgroupClass σ S
𝒜 : ι → σ
inst✝¹ : GradedRing 𝒜
inst✝ : Algebra.FiniteType (↥(𝒜 0)) S
s : Finset S
h₁ : Algebra.adjoin ↥(𝒜 0) ↑s = ⊤
n : S → ι
hn : ∀ i ∈ s, i ∈ 𝒜 (n i)
⊢ ∃ s, Algebra.adjoin ↥(𝒜 0) ↑s = ⊤ ∧ ∀ i ∈ s, ∃ n, n ≠ 0 ∧ i ∈ 𝒜 n
Module: Mathlib.RingTheory.GradedAlgebra.HomogeneousLocalization

Goal state before:
pp: ι : Type u_1
A : Type u_2
σ : Type u_3
inst✝² : CommRing A
inst✝¹ : SetLike σ A
inst✝ : AddSubmonoidClass σ A
𝒜 : ι → σ
x : Submonoid A
n : ℕ
y : HomogeneousLocalization 𝒜 x
⊢ (n • y).val = n • y.val

Tactic:
rw [val_smul, OreLocalization.nsmul_eq_nsmul]

Goal state after:
Module: Mathlib.AlgebraicGeometry.ProjectiveSpectrum.Scheme

Goal state before:
pp: A : Type u_1
σ : Type u_2
inst✝³ : CommRing A
inst✝² : SetLike σ A
inst✝¹ : AddSubgroupClass σ A
𝒜 : ℕ → σ
inst✝ : GradedRing 𝒜
f : A
m : ℕ
f_deg : f ∈ 𝒜 m
hm : 0 < m
q : ↑↑(Spec A⁰_ f).toPresheafedSpace
a : A
n : ℕ
hn : a ∈ 𝒜 (n * m)
⊢ a ∈ carrier f_deg q ↔
    HomogeneousLocalization.mk { deg := m * n, num := ⟨a, ⋯⟩, den := ⟨f ^ n, ⋯⟩, den_mem := ⋯ } ∈ q.asIdeal

Tactic:
rw [mem_carrier_iff_of_mem f_deg hm q a hn, iff_iff_eq, eq_comm,
    ← Ideal.IsPrime.pow_mem_iff_mem (α := A⁰_ f) inferInstance m hm]

Goal state after:
A : Type u_1
σ : Type u_2
inst✝³ : CommRing A
inst✝² : SetLike σ A
inst✝¹ : AddSubgroupClass σ A
𝒜 : ℕ → σ
inst✝ : GradedRing 𝒜
f : A
m : ℕ
f_deg : f ∈ 𝒜 m
hm : 0 < m
q : ↑↑(Spec A⁰_ f).toPresheafedSpace
a : A
n : ℕ
hn : a ∈ 𝒜 (n * m)
⊢ (HomogeneousLocalization.mk { deg := m * n, num := ⟨a, ⋯⟩, den := ⟨f ^ n, ⋯⟩, den_mem := ⋯ } ^ m ∈ q.asIdeal) =
    (HomogeneousLocalization.mk { deg := m * (n * m), num := ⟨a ^ m, ⋯⟩, den := ⟨f ^ (n * m), ⋯⟩, den_mem := ⋯ } ∈
      q.asIdeal)