Theorem: RingTheory.Sequence.IsWeaklyRegular.prototype_perm
File: Mathlib/RingTheory/Regular/RegularSequence.lean

tactic: exact .nil R _
state_before: case nil
R : Type u_1
S : Type u_2
M : Type u_3
M₂ : Type u_4
M₃ : Type u_5
M₄ : Type u_6
inst✝⁸ : CommRing R
inst✝⁷ : AddCommGroup M
inst✝⁶ : AddCommGroup M₂
inst✝⁵ : AddCommGroup M₃
inst✝⁴ : AddCommGroup M₄
inst✝³ : Module R M
inst✝² : Module R M₂
inst✝¹ : Module R M₃
inst✝ : Module R M₄
rs : List R
h✝ : IsWeaklyRegular M rs
rs' : List R
h'' : rs ~ rs'
h' :
  ∀ (a b : R) (rs' : List R),
    a :: b :: rs' <+~ rs →
      let K := torsionBy R (M ⧸ Ideal.ofList rs' • ⊤) b;
      K = a • K → K = ⊥
rs₁ rs₂ rs₀ : List R
H₁ H₃ : rs₀ ++ [] <+~ rs
h : IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) []
⊢ IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) []
state_after: no goals

tactic: let e := quotOfListConsSMulTopEquivQuotSMulTopOuter M r rs₀
state_before: case cons
R : Type u_1
S : Type u_2
M : Type u_3
M₂ : Type u_4
M₃ : Type u_5
M₄ : Type u_6
inst✝⁸ : CommRing R
inst✝⁷ : AddCommGroup M
inst✝⁶ : AddCommGroup M₂
inst✝⁵ : AddCommGroup M₃
inst✝⁴ : AddCommGroup M₄
inst✝³ : Module R M
inst✝² : Module R M₂
inst✝¹ : Module R M₃
inst✝ : Module R M₄
rs : List R
h✝ : IsWeaklyRegular M rs
rs' : List R
h'' : rs ~ rs'
h' :
  ∀ (a b : R) (rs' : List R),
    a :: b :: rs' <+~ rs →
      let K := torsionBy R (M ⧸ Ideal.ofList rs' • ⊤) b;
      K = a • K → K = ⊥
rs₁ rs₂ : List R
r : R
l₁✝ l₂✝ : List R
a✝ : l₁✝ ~ l₂✝
ih :
  ∀ (rs₀ : List R),
    rs₀ ++ l₁✝ <+~ rs →
      rs₀ ++ l₂✝ <+~ rs →
        IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) l₁✝ → IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) l₂✝
rs₀ : List R
H₁ : rs₀ ++ r :: l₁✝ <+~ rs
H₃ : rs₀ ++ r :: l₂✝ <+~ rs
h : IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) (r :: l₁✝)
⊢ IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) (r :: l₂✝)
state_after: case cons
R : Type u_1
S : Type u_2
M : Type u_3
M₂ : Type u_4
M₃ : Type u_5
M₄ : Type u_6
inst✝⁸ : CommRing R
inst✝⁷ : AddCommGroup M
inst✝⁶ : AddCommGroup M₂
inst✝⁵ : AddCommGroup M₃
inst✝⁴ : AddCommGroup M₄
inst✝³ : Module R M
inst✝² : Module R M₂
inst✝¹ : Module R M₃
inst✝ : Module R M₄
rs : List R
h✝ : IsWeaklyRegular M rs
rs' : List R
h'' : rs ~ rs'
h' :
  ∀ (a b : R) (rs' : List R),
    a :: b :: rs' <+~ rs →
      let K := torsionBy R (M ⧸ Ideal.ofList rs' • ⊤) b;
      K = a • K → K = ⊥
rs₁ rs₂ : List R
r : R
l₁✝ l₂✝ : List R
a✝ : l₁✝ ~ l₂✝
ih :
  ∀ (rs₀ : List R),
    rs₀ ++ l₁✝ <+~ rs →
      rs₀ ++ l₂✝ <+~ rs →
        IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) l₁✝ → IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) l₂✝
rs₀ : List R
H₁ : rs₀ ++ r :: l₁✝ <+~ rs
H₃ : rs₀ ++ r :: l₂✝ <+~ rs
h : IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) (r :: l₁✝)
e : (M ⧸ Ideal.ofList (r :: rs₀) • ⊤) ≃ₗ[R] QuotSMulTop r (M ⧸ Ideal.ofList rs₀ • ⊤) :=
  quotOfListConsSMulTopEquivQuotSMulTopOuter M r rs₀
⊢ IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) (r :: l₂✝)

tactic: rw [isWeaklyRegular_cons_iff, ← e.isWeaklyRegular_congr] at h ⊢
state_before: case cons
R : Type u_1
S : Type u_2
M : Type u_3
M₂ : Type u_4
M₃ : Type u_5
M₄ : Type u_6
inst✝⁸ : CommRing R
inst✝⁷ : AddCommGroup M
inst✝⁶ : AddCommGroup M₂
inst✝⁵ : AddCommGroup M₃
inst✝⁴ : AddCommGroup M₄
inst✝³ : Module R M
inst✝² : Module R M₂
inst✝¹ : Module R M₃
inst✝ : Module R M₄
rs : List R
h✝ : IsWeaklyRegular M rs
rs' : List R
h'' : rs ~ rs'
h' :
  ∀ (a b : R) (rs' : List R),
    a :: b :: rs' <+~ rs →
      let K := torsionBy R (M ⧸ Ideal.ofList rs' • ⊤) b;
      K = a • K → K = ⊥
rs₁ rs₂ : List R
r : R
l₁✝ l₂✝ : List R
a✝ : l₁✝ ~ l₂✝
ih :
  ∀ (rs₀ : List R),
    rs₀ ++ l₁✝ <+~ rs →
      rs₀ ++ l₂✝ <+~ rs →
        IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) l₁✝ → IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) l₂✝
rs₀ : List R
H₁ : rs₀ ++ r :: l₁✝ <+~ rs
H₃ : rs₀ ++ r :: l₂✝ <+~ rs
h : IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) (r :: l₁✝)
e : (M ⧸ Ideal.ofList (r :: rs₀) • ⊤) ≃ₗ[R] QuotSMulTop r (M ⧸ Ideal.ofList rs₀ • ⊤) :=
  quotOfListConsSMulTopEquivQuotSMulTopOuter M r rs₀
⊢ IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) (r :: l₂✝)
state_after: case cons
R : Type u_1
S : Type u_2
M : Type u_3
M₂ : Type u_4
M₃ : Type u_5
M₄ : Type u_6
inst✝⁸ : CommRing R
inst✝⁷ : AddCommGroup M
inst✝⁶ : AddCommGroup M₂
inst✝⁵ : AddCommGroup M₃
inst✝⁴ : AddCommGroup M₄
inst✝³ : Module R M
inst✝² : Module R M₂
inst✝¹ : Module R M₃
inst✝ : Module R M₄
rs : List R
h✝ : IsWeaklyRegular M rs
rs' : List R
h'' : rs ~ rs'
h' :
  ∀ (a b : R) (rs' : List R),
    a :: b :: rs' <+~ rs →
      let K := torsionBy R (M ⧸ Ideal.ofList rs' • ⊤) b;
      K = a • K → K = ⊥
rs₁ rs₂ : List R
r : R
l₁✝ l₂✝ : List R
a✝ : l₁✝ ~ l₂✝
ih :
  ∀ (rs₀ : List R),
    rs₀ ++ l₁✝ <+~ rs →
      rs₀ ++ l₂✝ <+~ rs →
        IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) l₁✝ → IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) l₂✝
rs₀ : List R
H₁ : rs₀ ++ r :: l₁✝ <+~ rs
H₃ : rs₀ ++ r :: l₂✝ <+~ rs
h : IsSMulRegular (M ⧸ Ideal.ofList rs₀ • ⊤) r ∧ IsWeaklyRegular (M ⧸ Ideal.ofList (r :: rs₀) • ⊤) l₁✝
e : (M ⧸ Ideal.ofList (r :: rs₀) • ⊤) ≃ₗ[R] QuotSMulTop r (M ⧸ Ideal.ofList rs₀ • ⊤) :=
  quotOfListConsSMulTopEquivQuotSMulTopOuter M r rs₀
⊢ IsSMulRegular (M ⧸ Ideal.ofList rs₀ • ⊤) r ∧ IsWeaklyRegular (M ⧸ Ideal.ofList (r :: rs₀) • ⊤) l₂✝

tactic: refine h.imp_right (ih (r :: rs₀) ?_ ?_) <;>
  exact List.perm_middle.subperm_right.mp ‹_›
state_before: case cons
R : Type u_1
S : Type u_2
M : Type u_3
M₂ : Type u_4
M₃ : Type u_5
M₄ : Type u_6
inst✝⁸ : CommRing R
inst✝⁷ : AddCommGroup M
inst✝⁶ : AddCommGroup M₂
inst✝⁵ : AddCommGroup M₃
inst✝⁴ : AddCommGroup M₄
inst✝³ : Module R M
inst✝² : Module R M₂
inst✝¹ : Module R M₃
inst✝ : Module R M₄
rs : List R
h✝ : IsWeaklyRegular M rs
rs' : List R
h'' : rs ~ rs'
h' :
  ∀ (a b : R) (rs' : List R),
    a :: b :: rs' <+~ rs →
      let K := torsionBy R (M ⧸ Ideal.ofList rs' • ⊤) b;
      K = a • K → K = ⊥
rs₁ rs₂ : List R
r : R
l₁✝ l₂✝ : List R
a✝ : l₁✝ ~ l₂✝
ih :
  ∀ (rs₀ : List R),
    rs₀ ++ l₁✝ <+~ rs →
      rs₀ ++ l₂✝ <+~ rs →
        IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) l₁✝ → IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) l₂✝
rs₀ : List R
H₁ : rs₀ ++ r :: l₁✝ <+~ rs
H₃ : rs₀ ++ r :: l₂✝ <+~ rs
h : IsSMulRegular (M ⧸ Ideal.ofList rs₀ • ⊤) r ∧ IsWeaklyRegular (M ⧸ Ideal.ofList (r :: rs₀) • ⊤) l₁✝
e : (M ⧸ Ideal.ofList (r :: rs₀) • ⊤) ≃ₗ[R] QuotSMulTop r (M ⧸ Ideal.ofList rs₀ • ⊤) :=
  quotOfListConsSMulTopEquivQuotSMulTopOuter M r rs₀
⊢ IsSMulRegular (M ⧸ Ideal.ofList rs₀ • ⊤) r ∧ IsWeaklyRegular (M ⧸ Ideal.ofList (r :: rs₀) • ⊤) l₂✝
state_after: no goals

tactic: rw [show ∀ x y z, x :: y :: z = [x, y] ++ z from fun _ _ _ => rfl,
  isWeaklyRegular_append_iff] at h ⊢
state_before: case swap
R : Type u_1
S : Type u_2
M : Type u_3
M₂ : Type u_4
M₃ : Type u_5
M₄ : Type u_6
inst✝⁸ : CommRing R
inst✝⁷ : AddCommGroup M
inst✝⁶ : AddCommGroup M₂
inst✝⁵ : AddCommGroup M₃
inst✝⁴ : AddCommGroup M₄
inst✝³ : Module R M
inst✝² : Module R M₂
inst✝¹ : Module R M₃
inst✝ : Module R M₄
rs : List R
h✝ : IsWeaklyRegular M rs
rs' : List R
h'' : rs ~ rs'
h' :
  ∀ (a b : R) (rs' : List R),
    a :: b :: rs' <+~ rs →
      let K := torsionBy R (M ⧸ Ideal.ofList rs' • ⊤) b;
      K = a • K → K = ⊥
rs₁ rs₂ : List R
a b : R
t rs₀ : List R
H₁ : rs₀ ++ b :: a :: t <+~ rs
H₃ : rs₀ ++ a :: b :: t <+~ rs
h : IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) (b :: a :: t)
⊢ IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) (a :: b :: t)
state_after: case swap
R : Type u_1
S : Type u_2
M : Type u_3
M₂ : Type u_4
M₃ : Type u_5
M₄ : Type u_6
inst✝⁸ : CommRing R
inst✝⁷ : AddCommGroup M
inst✝⁶ : AddCommGroup M₂
inst✝⁵ : AddCommGroup M₃
inst✝⁴ : AddCommGroup M₄
inst✝³ : Module R M
inst✝² : Module R M₂
inst✝¹ : Module R M₃
inst✝ : Module R M₄
rs : List R
h✝ : IsWeaklyRegular M rs
rs' : List R
h'' : rs ~ rs'
h' :
  ∀ (a b : R) (rs' : List R),
    a :: b :: rs' <+~ rs →
      let K := torsionBy R (M ⧸ Ideal.ofList rs' • ⊤) b;
      K = a • K → K = ⊥
rs₁ rs₂ : List R
a b : R
t rs₀ : List R
H₁ : rs₀ ++ b :: a :: t <+~ rs
H₃ : rs₀ ++ a :: b :: t <+~ rs
h :
  IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) [b, a] ∧
    IsWeaklyRegular ((M ⧸ Ideal.ofList rs₀ • ⊤) ⧸ Ideal.ofList [b, a] • ⊤) t
⊢ IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) [a, b] ∧
    IsWeaklyRegular ((M ⧸ Ideal.ofList rs₀ • ⊤) ⧸ Ideal.ofList [a, b] • ⊤) t

tactic: have : Ideal.ofList [b, a] = Ideal.ofList [a, b] :=
  congrArg Ideal.span <| Set.ext fun _ => (List.Perm.swap a b []).mem_iff
state_before: case swap
R : Type u_1
S : Type u_2
M : Type u_3
M₂ : Type u_4
M₃ : Type u_5
M₄ : Type u_6
inst✝⁸ : CommRing R
inst✝⁷ : AddCommGroup M
inst✝⁶ : AddCommGroup M₂
inst✝⁵ : AddCommGroup M₃
inst✝⁴ : AddCommGroup M₄
inst✝³ : Module R M
inst✝² : Module R M₂
inst✝¹ : Module R M₃
inst✝ : Module R M₄
rs : List R
h✝ : IsWeaklyRegular M rs
rs' : List R
h'' : rs ~ rs'
h' :
  ∀ (a b : R) (rs' : List R),
    a :: b :: rs' <+~ rs →
      let K := torsionBy R (M ⧸ Ideal.ofList rs' • ⊤) b;
      K = a • K → K = ⊥
rs₁ rs₂ : List R
a b : R
t rs₀ : List R
H₁ : rs₀ ++ b :: a :: t <+~ rs
H₃ : rs₀ ++ a :: b :: t <+~ rs
h :
  IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) [b, a] ∧
    IsWeaklyRegular ((M ⧸ Ideal.ofList rs₀ • ⊤) ⧸ Ideal.ofList [b, a] • ⊤) t
⊢ IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) [a, b] ∧
    IsWeaklyRegular ((M ⧸ Ideal.ofList rs₀ • ⊤) ⧸ Ideal.ofList [a, b] • ⊤) t
state_after: case swap
R : Type u_1
S : Type u_2
M : Type u_3
M₂ : Type u_4
M₃ : Type u_5
M₄ : Type u_6
inst✝⁸ : CommRing R
inst✝⁷ : AddCommGroup M
inst✝⁶ : AddCommGroup M₂
inst✝⁵ : AddCommGroup M₃
inst✝⁴ : AddCommGroup M₄
inst✝³ : Module R M
inst✝² : Module R M₂
inst✝¹ : Module R M₃
inst✝ : Module R M₄
rs : List R
h✝ : IsWeaklyRegular M rs
rs' : List R
h'' : rs ~ rs'
h' :
  ∀ (a b : R) (rs' : List R),
    a :: b :: rs' <+~ rs →
      let K := torsionBy R (M ⧸ Ideal.ofList rs' • ⊤) b;
      K = a • K → K = ⊥
rs₁ rs₂ : List R
a b : R
t rs₀ : List R
H₁ : rs₀ ++ b :: a :: t <+~ rs
H₃ : rs₀ ++ a :: b :: t <+~ rs
h :
  IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) [b, a] ∧
    IsWeaklyRegular ((M ⧸ Ideal.ofList rs₀ • ⊤) ⧸ Ideal.ofList [b, a] • ⊤) t
this : Ideal.ofList [b, a] = Ideal.ofList [a, b]
⊢ IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) [a, b] ∧
    IsWeaklyRegular ((M ⧸ Ideal.ofList rs₀ • ⊤) ⧸ Ideal.ofList [a, b] • ⊤) t

tactic: rw [(quotEquivOfEq _ _ (congrArg₂ _ this rfl)).isWeaklyRegular_congr] at h
state_before: case swap
R : Type u_1
S : Type u_2
M : Type u_3
M₂ : Type u_4
M₃ : Type u_5
M₄ : Type u_6
inst✝⁸ : CommRing R
inst✝⁷ : AddCommGroup M
inst✝⁶ : AddCommGroup M₂
inst✝⁵ : AddCommGroup M₃
inst✝⁴ : AddCommGroup M₄
inst✝³ : Module R M
inst✝² : Module R M₂
inst✝¹ : Module R M₃
inst✝ : Module R M₄
rs : List R
h✝ : IsWeaklyRegular M rs
rs' : List R
h'' : rs ~ rs'
h' :
  ∀ (a b : R) (rs' : List R),
    a :: b :: rs' <+~ rs →
      let K := torsionBy R (M ⧸ Ideal.ofList rs' • ⊤) b;
      K = a • K → K = ⊥
rs₁ rs₂ : List R
a b : R
t rs₀ : List R
H₁ : rs₀ ++ b :: a :: t <+~ rs
H₃ : rs₀ ++ a :: b :: t <+~ rs
h :
  IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) [b, a] ∧
    IsWeaklyRegular ((M ⧸ Ideal.ofList rs₀ • ⊤) ⧸ Ideal.ofList [b, a] • ⊤) t
this : Ideal.ofList [b, a] = Ideal.ofList [a, b]
⊢ IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) [a, b] ∧
    IsWeaklyRegular ((M ⧸ Ideal.ofList rs₀ • ⊤) ⧸ Ideal.ofList [a, b] • ⊤) t
state_after: case swap
R : Type u_1
S : Type u_2
M : Type u_3
M₂ : Type u_4
M₃ : Type u_5
M₄ : Type u_6
inst✝⁸ : CommRing R
inst✝⁷ : AddCommGroup M
inst✝⁶ : AddCommGroup M₂
inst✝⁵ : AddCommGroup M₃
inst✝⁴ : AddCommGroup M₄
inst✝³ : Module R M
inst✝² : Module R M₂
inst✝¹ : Module R M₃
inst✝ : Module R M₄
rs : List R
h✝ : IsWeaklyRegular M rs
rs' : List R
h'' : rs ~ rs'
h' :
  ∀ (a b : R) (rs' : List R),
    a :: b :: rs' <+~ rs →
      let K := torsionBy R (M ⧸ Ideal.ofList rs' • ⊤) b;
      K = a • K → K = ⊥
rs₁ rs₂ : List R
a b : R
t rs₀ : List R
H₁ : rs₀ ++ b :: a :: t <+~ rs
H₃ : rs₀ ++ a :: b :: t <+~ rs
h :
  IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) [b, a] ∧
    IsWeaklyRegular ((M ⧸ Ideal.ofList rs₀ • ⊤) ⧸ Ideal.ofList [a, b] • ⊤) t
this : Ideal.ofList [b, a] = Ideal.ofList [a, b]
⊢ IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) [a, b] ∧
    IsWeaklyRegular ((M ⧸ Ideal.ofList rs₀ • ⊤) ⧸ Ideal.ofList [a, b] • ⊤) t

tactic: rw [List.append_cons, List.append_cons, List.append_assoc _ [b] [a]] at H₁
state_before: case swap
R : Type u_1
S : Type u_2
M : Type u_3
M₂ : Type u_4
M₃ : Type u_5
M₄ : Type u_6
inst✝⁸ : CommRing R
inst✝⁷ : AddCommGroup M
inst✝⁶ : AddCommGroup M₂
inst✝⁵ : AddCommGroup M₃
inst✝⁴ : AddCommGroup M₄
inst✝³ : Module R M
inst✝² : Module R M₂
inst✝¹ : Module R M₃
inst✝ : Module R M₄
rs : List R
h✝ : IsWeaklyRegular M rs
rs' : List R
h'' : rs ~ rs'
h' :
  ∀ (a b : R) (rs' : List R),
    a :: b :: rs' <+~ rs →
      let K := torsionBy R (M ⧸ Ideal.ofList rs' • ⊤) b;
      K = a • K → K = ⊥
rs₁ rs₂ : List R
a b : R
t rs₀ : List R
H₁ : rs₀ ++ b :: a :: t <+~ rs
H₃ : rs₀ ++ a :: b :: t <+~ rs
h :
  IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) [b, a] ∧
    IsWeaklyRegular ((M ⧸ Ideal.ofList rs₀ • ⊤) ⧸ Ideal.ofList [a, b] • ⊤) t
this : Ideal.ofList [b, a] = Ideal.ofList [a, b]
⊢ IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) [a, b] ∧
    IsWeaklyRegular ((M ⧸ Ideal.ofList rs₀ • ⊤) ⧸ Ideal.ofList [a, b] • ⊤) t
state_after: case swap
R : Type u_1
S : Type u_2
M : Type u_3
M₂ : Type u_4
M₃ : Type u_5
M₄ : Type u_6
inst✝⁸ : CommRing R
inst✝⁷ : AddCommGroup M
inst✝⁶ : AddCommGroup M₂
inst✝⁵ : AddCommGroup M₃
inst✝⁴ : AddCommGroup M₄
inst✝³ : Module R M
inst✝² : Module R M₂
inst✝¹ : Module R M₃
inst✝ : Module R M₄
rs : List R
h✝ : IsWeaklyRegular M rs
rs' : List R
h'' : rs ~ rs'
h' :
  ∀ (a b : R) (rs' : List R),
    a :: b :: rs' <+~ rs →
      let K := torsionBy R (M ⧸ Ideal.ofList rs' • ⊤) b;
      K = a • K → K = ⊥
rs₁ rs₂ : List R
a b : R
t rs₀ : List R
H₁ : rs₀ ++ ([b] ++ [a]) ++ t <+~ rs
H₃ : rs₀ ++ a :: b :: t <+~ rs
h :
  IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) [b, a] ∧
    IsWeaklyRegular ((M ⧸ Ideal.ofList rs₀ • ⊤) ⧸ Ideal.ofList [a, b] • ⊤) t
this : Ideal.ofList [b, a] = Ideal.ofList [a, b]
⊢ IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) [a, b] ∧
    IsWeaklyRegular ((M ⧸ Ideal.ofList rs₀ • ⊤) ⧸ Ideal.ofList [a, b] • ⊤) t

tactic: apply (List.sublist_append_left (rs₀ ++ [b, a]) _).subperm.trans at H₁
state_before: case swap
R : Type u_1
S : Type u_2
M : Type u_3
M₂ : Type u_4
M₃ : Type u_5
M₄ : Type u_6
inst✝⁸ : CommRing R
inst✝⁷ : AddCommGroup M
inst✝⁶ : AddCommGroup M₂
inst✝⁵ : AddCommGroup M₃
inst✝⁴ : AddCommGroup M₄
inst✝³ : Module R M
inst✝² : Module R M₂
inst✝¹ : Module R M₃
inst✝ : Module R M₄
rs : List R
h✝ : IsWeaklyRegular M rs
rs' : List R
h'' : rs ~ rs'
h' :
  ∀ (a b : R) (rs' : List R),
    a :: b :: rs' <+~ rs →
      let K := torsionBy R (M ⧸ Ideal.ofList rs' • ⊤) b;
      K = a • K → K = ⊥
rs₁ rs₂ : List R
a b : R
t rs₀ : List R
H₁ : rs₀ ++ ([b] ++ [a]) ++ t <+~ rs
H₃ : rs₀ ++ a :: b :: t <+~ rs
h :
  IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) [b, a] ∧
    IsWeaklyRegular ((M ⧸ Ideal.ofList rs₀ • ⊤) ⧸ Ideal.ofList [a, b] • ⊤) t
this : Ideal.ofList [b, a] = Ideal.ofList [a, b]
⊢ IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) [a, b] ∧
    IsWeaklyRegular ((M ⧸ Ideal.ofList rs₀ • ⊤) ⧸ Ideal.ofList [a, b] • ⊤) t
state_after: case swap
R : Type u_1
S : Type u_2
M : Type u_3
M₂ : Type u_4
M₃ : Type u_5
M₄ : Type u_6
inst✝⁸ : CommRing R
inst✝⁷ : AddCommGroup M
inst✝⁶ : AddCommGroup M₂
inst✝⁵ : AddCommGroup M₃
inst✝⁴ : AddCommGroup M₄
inst✝³ : Module R M
inst✝² : Module R M₂
inst✝¹ : Module R M₃
inst✝ : Module R M₄
rs : List R
h✝ : IsWeaklyRegular M rs
rs' : List R
h'' : rs ~ rs'
h' :
  ∀ (a b : R) (rs' : List R),
    a :: b :: rs' <+~ rs →
      let K := torsionBy R (M ⧸ Ideal.ofList rs' • ⊤) b;
      K = a • K → K = ⊥
rs₁ rs₂ : List R
a b : R
t rs₀ : List R
H₃ : rs₀ ++ a :: b :: t <+~ rs
h :
  IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) [b, a] ∧
    IsWeaklyRegular ((M ⧸ Ideal.ofList rs₀ • ⊤) ⧸ Ideal.ofList [a, b] • ⊤) t
this : Ideal.ofList [b, a] = Ideal.ofList [a, b]
H₁ : rs₀ ++ [b, a] <+~ rs
⊢ IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) [a, b] ∧
    IsWeaklyRegular ((M ⧸ Ideal.ofList rs₀ • ⊤) ⧸ Ideal.ofList [a, b] • ⊤) t

tactic: apply List.perm_append_comm.subperm.trans at H₁
state_before: case swap
R : Type u_1
S : Type u_2
M : Type u_3
M₂ : Type u_4
M₃ : Type u_5
M₄ : Type u_6
inst✝⁸ : CommRing R
inst✝⁷ : AddCommGroup M
inst✝⁶ : AddCommGroup M₂
inst✝⁵ : AddCommGroup M₃
inst✝⁴ : AddCommGroup M₄
inst✝³ : Module R M
inst✝² : Module R M₂
inst✝¹ : Module R M₃
inst✝ : Module R M₄
rs : List R
h✝ : IsWeaklyRegular M rs
rs' : List R
h'' : rs ~ rs'
h' :
  ∀ (a b : R) (rs' : List R),
    a :: b :: rs' <+~ rs →
      let K := torsionBy R (M ⧸ Ideal.ofList rs' • ⊤) b;
      K = a • K → K = ⊥
rs₁ rs₂ : List R
a b : R
t rs₀ : List R
H₃ : rs₀ ++ a :: b :: t <+~ rs
h :
  IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) [b, a] ∧
    IsWeaklyRegular ((M ⧸ Ideal.ofList rs₀ • ⊤) ⧸ Ideal.ofList [a, b] • ⊤) t
this : Ideal.ofList [b, a] = Ideal.ofList [a, b]
H₁ : rs₀ ++ [b, a] <+~ rs
⊢ IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) [a, b] ∧
    IsWeaklyRegular ((M ⧸ Ideal.ofList rs₀ • ⊤) ⧸ Ideal.ofList [a, b] • ⊤) t
state_after: case swap
R : Type u_1
S : Type u_2
M : Type u_3
M₂ : Type u_4
M₃ : Type u_5
M₄ : Type u_6
inst✝⁸ : CommRing R
inst✝⁷ : AddCommGroup M
inst✝⁶ : AddCommGroup M₂
inst✝⁵ : AddCommGroup M₃
inst✝⁴ : AddCommGroup M₄
inst✝³ : Module R M
inst✝² : Module R M₂
inst✝¹ : Module R M₃
inst✝ : Module R M₄
rs : List R
h✝ : IsWeaklyRegular M rs
rs' : List R
h'' : rs ~ rs'
h' :
  ∀ (a b : R) (rs' : List R),
    a :: b :: rs' <+~ rs →
      let K := torsionBy R (M ⧸ Ideal.ofList rs' • ⊤) b;
      K = a • K → K = ⊥
rs₁ rs₂ : List R
a b : R
t rs₀ : List R
H₃ : rs₀ ++ a :: b :: t <+~ rs
h :
  IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) [b, a] ∧
    IsWeaklyRegular ((M ⧸ Ideal.ofList rs₀ • ⊤) ⧸ Ideal.ofList [a, b] • ⊤) t
this : Ideal.ofList [b, a] = Ideal.ofList [a, b]
H₁ : [b, a] ++ rs₀ <+~ rs
⊢ IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) [a, b] ∧
    IsWeaklyRegular ((M ⧸ Ideal.ofList rs₀ • ⊤) ⧸ Ideal.ofList [a, b] • ⊤) t

tactic: have H₂ := (h₁₂.append_left rs₀).subperm_right.mp H₁
state_before: case trans
R : Type u_1
S : Type u_2
M : Type u_3
M₂ : Type u_4
M₃ : Type u_5
M₄ : Type u_6
inst✝⁸ : CommRing R
inst✝⁷ : AddCommGroup M
inst✝⁶ : AddCommGroup M₂
inst✝⁵ : AddCommGroup M₃
inst✝⁴ : AddCommGroup M₄
inst✝³ : Module R M
inst✝² : Module R M₂
inst✝¹ : Module R M₃
inst✝ : Module R M₄
rs : List R
h✝ : IsWeaklyRegular M rs
rs' : List R
h'' : rs ~ rs'
h' :
  ∀ (a b : R) (rs' : List R),
    a :: b :: rs' <+~ rs →
      let K := torsionBy R (M ⧸ Ideal.ofList rs' • ⊤) b;
      K = a • K → K = ⊥
rs₁ rs₂ l₁✝ l₂✝ l₃✝ : List R
h₁₂ : l₁✝ ~ l₂✝
a✝ : l₂✝ ~ l₃✝
ih₁₂ :
  ∀ (rs₀ : List R),
    rs₀ ++ l₁✝ <+~ rs →
      rs₀ ++ l₂✝ <+~ rs →
        IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) l₁✝ → IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) l₂✝
ih₂₃ :
  ∀ (rs₀ : List R),
    rs₀ ++ l₂✝ <+~ rs →
      rs₀ ++ l₃✝ <+~ rs →
        IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) l₂✝ → IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) l₃✝
rs₀ : List R
H₁ : rs₀ ++ l₁✝ <+~ rs
H₃ : rs₀ ++ l₃✝ <+~ rs
h : IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) l₁✝
⊢ IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) l₃✝
state_after: case trans
R : Type u_1
S : Type u_2
M : Type u_3
M₂ : Type u_4
M₃ : Type u_5
M₄ : Type u_6
inst✝⁸ : CommRing R
inst✝⁷ : AddCommGroup M
inst✝⁶ : AddCommGroup M₂
inst✝⁵ : AddCommGroup M₃
inst✝⁴ : AddCommGroup M₄
inst✝³ : Module R M
inst✝² : Module R M₂
inst✝¹ : Module R M₃
inst✝ : Module R M₄
rs : List R
h✝ : IsWeaklyRegular M rs
rs' : List R
h'' : rs ~ rs'
h' :
  ∀ (a b : R) (rs' : List R),
    a :: b :: rs' <+~ rs →
      let K := torsionBy R (M ⧸ Ideal.ofList rs' • ⊤) b;
      K = a • K → K = ⊥
rs₁ rs₂ l₁✝ l₂✝ l₃✝ : List R
h₁₂ : l₁✝ ~ l₂✝
a✝ : l₂✝ ~ l₃✝
ih₁₂ :
  ∀ (rs₀ : List R),
    rs₀ ++ l₁✝ <+~ rs →
      rs₀ ++ l₂✝ <+~ rs →
        IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) l₁✝ → IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) l₂✝
ih₂₃ :
  ∀ (rs₀ : List R),
    rs₀ ++ l₂✝ <+~ rs →
      rs₀ ++ l₃✝ <+~ rs →
        IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) l₂✝ → IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) l₃✝
rs₀ : List R
H₁ : rs₀ ++ l₁✝ <+~ rs
H₃ : rs₀ ++ l₃✝ <+~ rs
h : IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) l₁✝
H₂ : rs₀ ++ l₂✝ <+~ rs
⊢ IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) l₃✝

tactic: exact ih₂₃ rs₀ H₂ H₃ (ih₁₂ rs₀ H₁ H₂ h)
state_before: case trans
R : Type u_1
S : Type u_2
M : Type u_3
M₂ : Type u_4
M₃ : Type u_5
M₄ : Type u_6
inst✝⁸ : CommRing R
inst✝⁷ : AddCommGroup M
inst✝⁶ : AddCommGroup M₂
inst✝⁵ : AddCommGroup M₃
inst✝⁴ : AddCommGroup M₄
inst✝³ : Module R M
inst✝² : Module R M₂
inst✝¹ : Module R M₃
inst✝ : Module R M₄
rs : List R
h✝ : IsWeaklyRegular M rs
rs' : List R
h'' : rs ~ rs'
h' :
  ∀ (a b : R) (rs' : List R),
    a :: b :: rs' <+~ rs →
      let K := torsionBy R (M ⧸ Ideal.ofList rs' • ⊤) b;
      K = a • K → K = ⊥
rs₁ rs₂ l₁✝ l₂✝ l₃✝ : List R
h₁₂ : l₁✝ ~ l₂✝
a✝ : l₂✝ ~ l₃✝
ih₁₂ :
  ∀ (rs₀ : List R),
    rs₀ ++ l₁✝ <+~ rs →
      rs₀ ++ l₂✝ <+~ rs →
        IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) l₁✝ → IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) l₂✝
ih₂₃ :
  ∀ (rs₀ : List R),
    rs₀ ++ l₂✝ <+~ rs →
      rs₀ ++ l₃✝ <+~ rs →
        IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) l₂✝ → IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) l₃✝
rs₀ : List R
H₁ : rs₀ ++ l₁✝ <+~ rs
H₃ : rs₀ ++ l₃✝ <+~ rs
h : IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) l₁✝
H₂ : rs₀ ++ l₂✝ <+~ rs
⊢ IsWeaklyRegular (M ⧸ Ideal.ofList rs₀ • ⊤) l₃✝
state_after: no goals