Module: Mathlib.RingTheory.Localization.Finiteness

Goal state before:
pp: case e'_2
R : Type u_1
S : Type u_2
inst✝⁷ : CommSemiring R
inst✝⁶ : CommSemiring S
M : Submonoid R
S' : Type u_4
inst✝⁵ : CommSemiring S'
inst✝⁴ : Algebra S S'
inst✝³ : Algebra R S
inst✝² : Algebra R S'
inst✝¹ : IsScalarTower R S S'
inst✝ : IsLocalization (Submonoid.map (algebraMap R S) M) S'
x : S
s : Finset S'
g : S →ₐ[R] S' := AlgHom.mk' (algebraMap S S') ⋯
g_apply : ∀ (x : S), g x = (algebraMap S S') x
y : ↥(Submonoid.map (algebraMap R S) M) := commonDenomOfFinset (Submonoid.map (algebraMap R S) M) s
y' : R
hy' : y' ∈ ↑M
e : (algebraMap R S) y' = ↑y
this : (algebraMap R S) y' • ↑s = y' • ↑s
hx₁ : y' • Submodule.span R ↑s = Submodule.span R (⇑g '' ↑(finsetIntegerMultiple (Submonoid.map (algebraMap R S) M) s))
x' : S
hx' : x' ∈ ↑(Submodule.span R ↑(finsetIntegerMultiple (Submonoid.map (algebraMap R S) M) s))
hx'' : (algebraMap S S') x' = (Algebra.linearMap S S') (y' • x)
a : R
ha₁ : a ∈ ↑M
ha₂ : ↑⟨(algebraMap R S) a, ⋯⟩ * x' = ↑⟨(algebraMap R S) a, ⋯⟩ * y' • x
⊢ (⟨a, ha₁⟩ * ⟨y', hy'⟩) • x = ↑⟨(algebraMap R S) a, ⋯⟩ * y' • x

pp: case e'_3
R : Type u_1
S : Type u_2
inst✝⁷ : CommSemiring R
inst✝⁶ : CommSemiring S
M : Submonoid R
S' : Type u_4
inst✝⁵ : CommSemiring S'
inst✝⁴ : Algebra S S'
inst✝³ : Algebra R S
inst✝² : Algebra R S'
inst✝¹ : IsScalarTower R S S'
inst✝ : IsLocalization (Submonoid.map (algebraMap R S) M) S'
x : S
s : Finset S'
g : S →ₐ[R] S' := AlgHom.mk' (algebraMap S S') ⋯
g_apply : ∀ (x : S), g x = (algebraMap S S') x
y : ↥(Submonoid.map (algebraMap R S) M) := commonDenomOfFinset (Submonoid.map (algebraMap R S) M) s
y' : R
hy' : y' ∈ ↑M
e : (algebraMap R S) y' = ↑y
this : (algebraMap R S) y' • ↑s = y' • ↑s
hx₁ : y' • Submodule.span R ↑s = Submodule.span R (⇑g '' ↑(finsetIntegerMultiple (Submonoid.map (algebraMap R S) M) s))
x' : S
hx' : x' ∈ ↑(Submodule.span R ↑(finsetIntegerMultiple (Submonoid.map (algebraMap R S) M) s))
hx'' : (algebraMap S S') x' = (Algebra.linearMap S S') (y' • x)
a : R
ha₁ : a ∈ ↑M
ha₂ : ↑⟨(algebraMap R S) a, ⋯⟩ * x' = ↑⟨(algebraMap R S) a, ⋯⟩ * y' • x
⊢ a • x' = ↑⟨(algebraMap R S) a, ⋯⟩ * x'

Tactic:
· rw [Subtype.coe_mk, Submonoid.smul_def, Submonoid.coe_mul, ← smul_smul]
    exact Algebra.smul_def _ _

Goal state after:
case e'_3
R : Type u_1
S : Type u_2
inst✝⁷ : CommSemiring R
inst✝⁶ : CommSemiring S
M : Submonoid R
S' : Type u_4
inst✝⁵ : CommSemiring S'
inst✝⁴ : Algebra S S'
inst✝³ : Algebra R S
inst✝² : Algebra R S'
inst✝¹ : IsScalarTower R S S'
inst✝ : IsLocalization (Submonoid.map (algebraMap R S) M) S'
x : S
s : Finset S'
g : S →ₐ[R] S' := AlgHom.mk' (algebraMap S S') ⋯
g_apply : ∀ (x : S), g x = (algebraMap S S') x
y : ↥(Submonoid.map (algebraMap R S) M) := commonDenomOfFinset (Submonoid.map (algebraMap R S) M) s
y' : R
hy' : y' ∈ ↑M
e : (algebraMap R S) y' = ↑y
this : (algebraMap R S) y' • ↑s = y' • ↑s
hx₁ : y' • Submodule.span R ↑s = Submodule.span R (⇑g '' ↑(finsetIntegerMultiple (Submonoid.map (algebraMap R S) M) s))
x' : S
hx' : x' ∈ ↑(Submodule.span R ↑(finsetIntegerMultiple (Submonoid.map (algebraMap R S) M) s))
hx'' : (algebraMap S S') x' = (Algebra.linearMap S S') (y' • x)
a : R
ha₁ : a ∈ ↑M
ha₂ : ↑⟨(algebraMap R S) a, ⋯⟩ * x' = ↑⟨(algebraMap R S) a, ⋯⟩ * y' • x
⊢ a • x' = ↑⟨(algebraMap R S) a, ⋯⟩ * x'