-- Mathlib/Algebra/Lie/Solvable.lean
theorem coe_derivedSeries_eq_int (k : ℕ) :
    (derivedSeries R L k : Set L) = (derivedSeries ℤ L k : Set L)

Proof state:
case succ
R : Type u
L : Type v
inst✝² : CommRing R
inst✝¹ : LieRing L
inst✝ : LieAlgebra R L
k : ℕ
ih : ∀ (x : L), x ∈ ↑↑(derivedSeriesOfIdeal R L k ⊤) ↔ x ∈ ↑↑(derivedSeriesOfIdeal ℤ L k ⊤)
⊢ ↑(Submodule.span R {x | ∃ x_1 ∈ derivedSeriesOfIdeal R L k ⊤, ∃ n ∈ derivedSeriesOfIdeal R L k ⊤, ⁅x_1, n⁆ = x}) =
    ↑(Submodule.span ℤ {x | ∃ x_1 ∈ derivedSeriesOfIdeal ℤ L k ⊤, ∃ n ∈ derivedSeriesOfIdeal ℤ L k ⊤, ⁅x_1, n⁆ = x})

Tactic:
simp only [SetLike.mem_coe, LieSubmodule.mem_toSubmodule] at ih

Result:
case succ
R : Type u
L : Type v
inst✝² : CommRing R
inst✝¹ : LieRing L
inst✝ : LieAlgebra R L
k : ℕ
ih : ∀ (x : L), x ∈ derivedSeriesOfIdeal R L k ⊤ ↔ x ∈ derivedSeriesOfIdeal ℤ L k ⊤
⊢ ↑(Submodule.span R {x | ∃ x_1 ∈ derivedSeriesOfIdeal R L k ⊤, ∃ n ∈ derivedSeriesOfIdeal R L k ⊤, ⁅x_1, n⁆ = x}) =
    ↑(Submodule.span ℤ {x | ∃ x_1 ∈ derivedSeriesOfIdeal ℤ L k ⊤, ∃ n ∈ derivedSeriesOfIdeal ℤ L k ⊤, ⁅x_1, n⁆ = x})

Proof state:
case succ
R : Type u
L : Type v
inst✝² : CommRing R
inst✝¹ : LieRing L
inst✝ : LieAlgebra R L
k : ℕ
ih : ↑↑(derivedSeriesOfIdeal R L k ⊤) = ↑↑(derivedSeriesOfIdeal ℤ L k ⊤)
⊢ ↑↑(derivedSeriesOfIdeal R L (k + 1) ⊤) = ↑↑(derivedSeriesOfIdeal ℤ L (k + 1) ⊤)

Tactic:
rw [derivedSeriesOfIdeal_succ, derivedSeriesOfIdeal_succ]

Result:
case succ
R : Type u
L : Type v
inst✝² : CommRing R
inst✝¹ : LieRing L
inst✝ : LieAlgebra R L
k : ℕ
ih : ↑↑(derivedSeriesOfIdeal R L k ⊤) = ↑↑(derivedSeriesOfIdeal ℤ L k ⊤)
⊢ ↑↑⁅derivedSeriesOfIdeal R L k ⊤, derivedSeriesOfIdeal R L k ⊤⁆ =
    ↑↑⁅derivedSeriesOfIdeal ℤ L k ⊤, derivedSeriesOfIdeal ℤ L k ⊤⁆

Proof state:
case succ.a
R : Type u
L : Type v
inst✝² : CommRing R
inst✝¹ : LieRing L
inst✝ : LieAlgebra R L
k : ℕ
ih : ∀ (x : L), x ∈ derivedSeriesOfIdeal R L k ⊤ ↔ x ∈ derivedSeriesOfIdeal ℤ L k ⊤
⊢ ↑(Submodule.span ℤ {x | ∃ x_1 ∈ derivedSeriesOfIdeal ℤ L k ⊤, ∃ n ∈ derivedSeriesOfIdeal ℤ L k ⊤, ⁅x_1, n⁆ = x}) ≤
    ↑(Submodule.span R {x | ∃ x_1 ∈ derivedSeriesOfIdeal ℤ L k ⊤, ∃ n ∈ derivedSeriesOfIdeal ℤ L k ⊤, ⁅x_1, n⁆ = x})

Tactic:
simp only [← ih]

Result:
case succ.a
R : Type u
L : Type v
inst✝² : CommRing R
inst✝¹ : LieRing L
inst✝ : LieAlgebra R L
k : ℕ
ih : ∀ (x : L), x ∈ derivedSeriesOfIdeal R L k ⊤ ↔ x ∈ derivedSeriesOfIdeal ℤ L k ⊤
⊢ ↑(Submodule.span ℤ {x | ∃ x_1 ∈ derivedSeriesOfIdeal R L k ⊤, ∃ n ∈ derivedSeriesOfIdeal R L k ⊤, ⁅x_1, n⁆ = x}) ≤
    ↑(Submodule.span R {x | ∃ x_1 ∈ derivedSeriesOfIdeal R L k ⊤, ∃ n ∈ derivedSeriesOfIdeal R L k ⊤, ⁅x_1, n⁆ = x})

Proof state:
R : Type u
L : Type v
inst✝² : CommRing R
inst✝¹ : LieRing L
inst✝ : LieAlgebra R L
k : ℕ
⊢ ↑(derivedSeries R L k) = ↑(derivedSeries ℤ L k)

Tactic:
rw [← LieSubmodule.coe_toSubmodule, ← LieSubmodule.coe_toSubmodule, derivedSeries_def,
  derivedSeries_def]

Result:
R : Type u
L : Type v
inst✝² : CommRing R
inst✝¹ : LieRing L
inst✝ : LieAlgebra R L
k : ℕ
⊢ ↑↑(derivedSeriesOfIdeal R L k ⊤) = ↑↑(derivedSeriesOfIdeal ℤ L k ⊤)

Proof state:
case succ.a
R : Type u
L : Type v
inst✝² : CommRing R
inst✝¹ : LieRing L
inst✝ : LieAlgebra R L
k : ℕ
ih : ∀ (x : L), x ∈ derivedSeriesOfIdeal R L k ⊤ ↔ x ∈ derivedSeriesOfIdeal ℤ L k ⊤
⊢ ↑(Submodule.span ℤ {x | ∃ x_1 ∈ derivedSeriesOfIdeal R L k ⊤, ∃ n ∈ derivedSeriesOfIdeal R L k ⊤, ⁅x_1, n⁆ = x}) ≤
    ↑(Submodule.span R {x | ∃ x_1 ∈ derivedSeriesOfIdeal R L k ⊤, ∃ n ∈ derivedSeriesOfIdeal R L k ⊤, ⁅x_1, n⁆ = x})

Tactic:
apply coe_derivedSeries_eq_int_aux _ _ L k

Result:
case succ.a
R : Type u
L : Type v
inst✝² : CommRing R
inst✝¹ : LieRing L
inst✝ : LieAlgebra R L
k : ℕ
ih : ∀ (x : L), x ∈ derivedSeriesOfIdeal R L k ⊤ ↔ x ∈ derivedSeriesOfIdeal ℤ L k ⊤
⊢ ∀ (x : L), x ∈ derivedSeriesOfIdeal ℤ L k ⊤ ↔ x ∈ derivedSeriesOfIdeal R L k ⊤

Proof state:
case succ
R : Type u
L : Type v
inst✝² : CommRing R
inst✝¹ : LieRing L
inst✝ : LieAlgebra R L
k : ℕ
ih : ∀ (x : L), x ∈ derivedSeriesOfIdeal R L k ⊤ ↔ x ∈ derivedSeriesOfIdeal ℤ L k ⊤
⊢ ↑(Submodule.span R {x | ∃ x_1 ∈ derivedSeriesOfIdeal ℤ L k ⊤, ∃ n ∈ derivedSeriesOfIdeal ℤ L k ⊤, ⁅x_1, n⁆ = x}) =
    ↑(Submodule.span ℤ {x | ∃ x_1 ∈ derivedSeriesOfIdeal ℤ L k ⊤, ∃ n ∈ derivedSeriesOfIdeal ℤ L k ⊤, ⁅x_1, n⁆ = x})

Tactic:
apply le_antisymm

Result:
case succ.a
R : Type u
L : Type v
inst✝² : CommRing R
inst✝¹ : LieRing L
inst✝ : LieAlgebra R L
k : ℕ
ih : ∀ (x : L), x ∈ derivedSeriesOfIdeal R L k ⊤ ↔ x ∈ derivedSeriesOfIdeal ℤ L k ⊤
⊢ ↑(Submodule.span R {x | ∃ x_1 ∈ derivedSeriesOfIdeal ℤ L k ⊤, ∃ n ∈ derivedSeriesOfIdeal ℤ L k ⊤, ⁅x_1, n⁆ = x}) ≤
    ↑(Submodule.span ℤ {x | ∃ x_1 ∈ derivedSeriesOfIdeal ℤ L k ⊤, ∃ n ∈ derivedSeriesOfIdeal ℤ L k ⊤, ⁅x_1, n⁆ = x})

case succ.a
R : Type u
L : Type v
inst✝² : CommRing R
inst✝¹ : LieRing L
inst✝ : LieAlgebra R L
k : ℕ
ih : ∀ (x : L), x ∈ derivedSeriesOfIdeal R L k ⊤ ↔ x ∈ derivedSeriesOfIdeal ℤ L k ⊤
⊢ ↑(Submodule.span ℤ {x | ∃ x_1 ∈ derivedSeriesOfIdeal ℤ L k ⊤, ∃ n ∈ derivedSeriesOfIdeal ℤ L k ⊤, ⁅x_1, n⁆ = x}) ≤
    ↑(Submodule.span R {x | ∃ x_1 ∈ derivedSeriesOfIdeal ℤ L k ⊤, ∃ n ∈ derivedSeriesOfIdeal ℤ L k ⊤, ⁅x_1, n⁆ = x})

Proof state:
case succ
R : Type u
L : Type v
inst✝² : CommRing R
inst✝¹ : LieRing L
inst✝ : LieAlgebra R L
k : ℕ
ih : ↑↑(derivedSeriesOfIdeal R L k ⊤) = ↑↑(derivedSeriesOfIdeal ℤ L k ⊤)
⊢ ↑(Submodule.span R {x | ∃ x_1 ∈ derivedSeriesOfIdeal R L k ⊤, ∃ n ∈ derivedSeriesOfIdeal R L k ⊤, ⁅x_1, n⁆ = x}) =
    ↑(Submodule.span ℤ {x | ∃ x_1 ∈ derivedSeriesOfIdeal ℤ L k ⊤, ∃ n ∈ derivedSeriesOfIdeal ℤ L k ⊤, ⁅x_1, n⁆ = x})

Tactic:
rw [Set.ext_iff] at ih

Result:
case succ
R : Type u
L : Type v
inst✝² : CommRing R
inst✝¹ : LieRing L
inst✝ : LieAlgebra R L
k : ℕ
ih : ∀ (x : L), x ∈ ↑↑(derivedSeriesOfIdeal R L k ⊤) ↔ x ∈ ↑↑(derivedSeriesOfIdeal ℤ L k ⊤)
⊢ ↑(Submodule.span R {x | ∃ x_1 ∈ derivedSeriesOfIdeal R L k ⊤, ∃ n ∈ derivedSeriesOfIdeal R L k ⊤, ⁅x_1, n⁆ = x}) =
    ↑(Submodule.span ℤ {x | ∃ x_1 ∈ derivedSeriesOfIdeal ℤ L k ⊤, ∃ n ∈ derivedSeriesOfIdeal ℤ L k ⊤, ⁅x_1, n⁆ = x})

Proof state:
case zero
R : Type u
L : Type v
inst✝² : CommRing R
inst✝¹ : LieRing L
inst✝ : LieAlgebra R L
⊢ ↑↑(derivedSeriesOfIdeal R L 0 ⊤) = ↑↑(derivedSeriesOfIdeal ℤ L 0 ⊤)

Tactic:
rfl

Result:
no goals

Proof state:
case succ
R : Type u
L : Type v
inst✝² : CommRing R
inst✝¹ : LieRing L
inst✝ : LieAlgebra R L
k : ℕ
ih : ↑↑(derivedSeriesOfIdeal R L k ⊤) = ↑↑(derivedSeriesOfIdeal ℤ L k ⊤)
⊢ ↑↑⁅derivedSeriesOfIdeal R L k ⊤, derivedSeriesOfIdeal R L k ⊤⁆ =
    ↑↑⁅derivedSeriesOfIdeal ℤ L k ⊤, derivedSeriesOfIdeal ℤ L k ⊤⁆

Tactic:
rw [LieSubmodule.lieIdeal_oper_eq_linear_span', LieSubmodule.lieIdeal_oper_eq_linear_span']

Result:
case succ
R : Type u
L : Type v
inst✝² : CommRing R
inst✝¹ : LieRing L
inst✝ : LieAlgebra R L
k : ℕ
ih : ↑↑(derivedSeriesOfIdeal R L k ⊤) = ↑↑(derivedSeriesOfIdeal ℤ L k ⊤)
⊢ ↑(Submodule.span R {x | ∃ x_1 ∈ derivedSeriesOfIdeal R L k ⊤, ∃ n ∈ derivedSeriesOfIdeal R L k ⊤, ⁅x_1, n⁆ = x}) =
    ↑(Submodule.span ℤ {x | ∃ x_1 ∈ derivedSeriesOfIdeal ℤ L k ⊤, ∃ n ∈ derivedSeriesOfIdeal ℤ L k ⊤, ⁅x_1, n⁆ = x})

Proof state:
case succ.a
R : Type u
L : Type v
inst✝² : CommRing R
inst✝¹ : LieRing L
inst✝ : LieAlgebra R L
k : ℕ
ih : ∀ (x : L), x ∈ derivedSeriesOfIdeal R L k ⊤ ↔ x ∈ derivedSeriesOfIdeal ℤ L k ⊤
⊢ ∀ (x : L), x ∈ derivedSeriesOfIdeal ℤ L k ⊤ ↔ x ∈ derivedSeriesOfIdeal R L k ⊤

Tactic:
simp [ih]

Result:
no goals