Module: Mathlib.RingTheory.FinitePresentation

Goal state before:
pp: case refine_3
R : Type w₁
A : Type w₂
B : Type w₃
inst✝⁸ : CommRing R
inst✝⁷ : CommRing A
inst✝⁶ : Algebra R A
inst✝⁵ : CommRing B
inst✝⁴ : Algebra R B
inst✝³ : Algebra A B
inst✝² : IsScalarTower R A B
inst✝¹ : FinitePresentation R B
inst✝ : FiniteType R A
n : ℕ
f : MvPolynomial (Fin n) R →ₐ[R] B
hf : Surjective ⇑f
s : Finset (MvPolynomial (Fin n) R)
hs : Ideal.span ↑s = RingHom.ker f.toRingHom
RX : Type (max w₁ 0) := MvPolynomial (Fin n) R
AX : Type (max w₂ 0) := MvPolynomial (Fin n) A
t : Finset A
ht : adjoin R ↑t = ⊤
t' : ↥t → MvPolynomial (Fin n) R
ht' : ∀ (i : ↥t), f (t' i) = (algebraMap A B) ↑i
ht'' : adjoin R (⇑(algebraMap A AX) '' ↑t ∪ Set.range MvPolynomial.X) = ⊤
g : ↥t → AX := fun x ↦ MvPolynomial.C ↑x - (MvPolynomial.map (algebraMap R A)) (t' x)
s₀✝ : Set (MvPolynomial (Fin n) A) := ⇑(MvPolynomial.map (algebraMap R A)) '' ↑s ∪ Set.range g
I : Ideal (MvPolynomial (Fin n) A) := RingHom.ker (MvPolynomial.aeval (⇑f ∘ MvPolynomial.X))
leI :
  Ideal.span (⇑(MvPolynomial.map (algebraMap R A)) '' ↑s ∪ Set.range g) ≤
    RingHom.ker (MvPolynomial.aeval (⇑f ∘ MvPolynomial.X))
x : MvPolynomial (Fin n) A
hx : (MvPolynomial.aeval (⇑f ∘ MvPolynomial.X)) x = 0
s₀ : Set (MvPolynomial (Fin n) A) := ⇑(MvPolynomial.map (algebraMap R A)) '' ↑s ∪ Set.range g
this : x ∈ adjoin R (⇑(algebraMap A AX) '' ↑t ∪ Set.range MvPolynomial.X)
x✝ y✝ : MvPolynomial (Fin n) A
hx✝ : x✝ ∈ adjoin R (⇑(algebraMap A AX) '' ↑t ∪ Set.range MvPolynomial.X)
hy✝ : y✝ ∈ adjoin R (⇑(algebraMap A AX) '' ↑t ∪ Set.range MvPolynomial.X)
h₁ : x✝ ∈ (MvPolynomial.map (algebraMap R A)).range.toAddSubmonoid ⊔ (Ideal.span s₀).toAddSubmonoid
⊢ y✝ ∈ (MvPolynomial.map (algebraMap R A)).range.toAddSubmonoid ⊔ (Ideal.span s₀).toAddSubmonoid →
    x✝ + y✝ ∈ (MvPolynomial.map (algebraMap R A)).range.toAddSubmonoid ⊔ (Ideal.span s₀).toAddSubmonoid

Tactic:
h₂

Goal state after:
case refine_3
R : Type w₁
A : Type w₂
B : Type w₃
inst✝⁸ : CommRing R
inst✝⁷ : CommRing A
inst✝⁶ : Algebra R A
inst✝⁵ : CommRing B
inst✝⁴ : Algebra R B
inst✝³ : Algebra A B
inst✝² : IsScalarTower R A B
inst✝¹ : FinitePresentation R B
inst✝ : FiniteType R A
n : ℕ
f : MvPolynomial (Fin n) R →ₐ[R] B
hf : Surjective ⇑f
s : Finset (MvPolynomial (Fin n) R)
hs : Ideal.span ↑s = RingHom.ker f.toRingHom
RX : Type (max w₁ 0) := MvPolynomial (Fin n) R
AX : Type (max w₂ 0) := MvPolynomial (Fin n) A
t : Finset A
ht : adjoin R ↑t = ⊤
t' : ↥t → MvPolynomial (Fin n) R
ht' : ∀ (i : ↥t), f (t' i) = (algebraMap A B) ↑i
ht'' : adjoin R (⇑(algebraMap A AX) '' ↑t ∪ Set.range MvPolynomial.X) = ⊤
g : ↥t → AX := fun x ↦ MvPolynomial.C ↑x - (MvPolynomial.map (algebraMap R A)) (t' x)
s₀✝ : Set (MvPolynomial (Fin n) A) := ⇑(MvPolynomial.map (algebraMap R A)) '' ↑s ∪ Set.range g
I : Ideal (MvPolynomial (Fin n) A) := RingHom.ker (MvPolynomial.aeval (⇑f ∘ MvPolynomial.X))
leI :
  Ideal.span (⇑(MvPolynomial.map (algebraMap R A)) '' ↑s ∪ Set.range g) ≤
    RingHom.ker (MvPolynomial.aeval (⇑f ∘ MvPolynomial.X))
x : MvPolynomial (Fin n) A
hx : (MvPolynomial.aeval (⇑f ∘ MvPolynomial.X)) x = 0
s₀ : Set (MvPolynomial (Fin n) A) := ⇑(MvPolynomial.map (algebraMap R A)) '' ↑s ∪ Set.range g
this : x ∈ adjoin R (⇑(algebraMap A AX) '' ↑t ∪ Set.range MvPolynomial.X)
x✝ y✝ : MvPolynomial (Fin n) A
hx✝ : x✝ ∈ adjoin R (⇑(algebraMap A AX) '' ↑t ∪ Set.range MvPolynomial.X)
hy✝ : y✝ ∈ adjoin R (⇑(algebraMap A AX) '' ↑t ∪ Set.range MvPolynomial.X)
h₁ : x✝ ∈ (MvPolynomial.map (algebraMap R A)).range.toAddSubmonoid ⊔ (Ideal.span s₀).toAddSubmonoid
h₂ : y✝ ∈ (MvPolynomial.map (algebraMap R A)).range.toAddSubmonoid ⊔ (Ideal.span s₀).toAddSubmonoid
⊢ x✝ + y✝ ∈ (MvPolynomial.map (algebraMap R A)).range.toAddSubmonoid ⊔ (Ideal.span s₀).toAddSubmonoid