Theorem: Turing.TM1to1.trTape'_move_right
File: Mathlib/Computability/TuringMachine.lean

tactic: suffices ∀ i L, (Tape.move Dir.right)^[i] ((Tape.move Dir.left)^[i] L) = L by
  refine (Eq.symm ?_).trans (this n _)
  simp only [trTape'_move_left, ListBlank.cons_head_tail, ListBlank.head_cons,
    ListBlank.tail_cons]
state_before: Γ : Type u_1
inst✝² : Inhabited Γ
Λ : Type u_2
inst✝¹ : Inhabited Λ
σ : Type u_3
inst✝ : Inhabited σ
n : ℕ
enc : Γ → Vector Bool n
dec : Vector Bool n → Γ
enc0 : enc default = Vector.replicate n false
M : Λ → Stmt₁
L R : ListBlank Γ
⊢ (Tape.move Dir.right)^[n] (trTape' enc0 L R) = trTape' enc0 (ListBlank.cons R.head L) R.tail
state_after: Γ : Type u_1
inst✝² : Inhabited Γ
Λ : Type u_2
inst✝¹ : Inhabited Λ
σ : Type u_3
inst✝ : Inhabited σ
n : ℕ
enc : Γ → Vector Bool n
dec : Vector Bool n → Γ
enc0 : enc default = Vector.replicate n false
M : Λ → Stmt₁
L R : ListBlank Γ
⊢ ∀ (i : ℕ) (L : Tape Bool), (Tape.move Dir.right)^[i] ((Tape.move Dir.left)^[i] L) = L

tactic: intro i _
state_before: Γ : Type u_1
inst✝² : Inhabited Γ
Λ : Type u_2
inst✝¹ : Inhabited Λ
σ : Type u_3
inst✝ : Inhabited σ
n : ℕ
enc : Γ → Vector Bool n
dec : Vector Bool n → Γ
enc0 : enc default = Vector.replicate n false
M : Λ → Stmt₁
L R : ListBlank Γ
⊢ ∀ (i : ℕ) (L : Tape Bool), (Tape.move Dir.right)^[i] ((Tape.move Dir.left)^[i] L) = L
state_after: Γ : Type u_1
inst✝² : Inhabited Γ
Λ : Type u_2
inst✝¹ : Inhabited Λ
σ : Type u_3
inst✝ : Inhabited σ
n : ℕ
enc : Γ → Vector Bool n
dec : Vector Bool n → Γ
enc0 : enc default = Vector.replicate n false
M : Λ → Stmt₁
L R : ListBlank Γ
i : ℕ
L✝ : Tape Bool
⊢ (Tape.move Dir.right)^[i] ((Tape.move Dir.left)^[i] L✝) = L✝

tactic: induction' i with i IH
state_before: Γ : Type u_1
inst✝² : Inhabited Γ
Λ : Type u_2
inst✝¹ : Inhabited Λ
σ : Type u_3
inst✝ : Inhabited σ
n : ℕ
enc : Γ → Vector Bool n
dec : Vector Bool n → Γ
enc0 : enc default = Vector.replicate n false
M : Λ → Stmt₁
L R : ListBlank Γ
i : ℕ
L✝ : Tape Bool
⊢ (Tape.move Dir.right)^[i] ((Tape.move Dir.left)^[i] L✝) = L✝
state_after: case zero
Γ : Type u_1
inst✝² : Inhabited Γ
Λ : Type u_2
inst✝¹ : Inhabited Λ
σ : Type u_3
inst✝ : Inhabited σ
n : ℕ
enc : Γ → Vector Bool n
dec : Vector Bool n → Γ
enc0 : enc default = Vector.replicate n false
M : Λ → Stmt₁
L R : ListBlank Γ
L✝ : Tape Bool
⊢ (Tape.move Dir.right)^[0] ((Tape.move Dir.left)^[0] L✝) = L✝

case succ
Γ : Type u_1
inst✝² : Inhabited Γ
Λ : Type u_2
inst✝¹ : Inhabited Λ
σ : Type u_3
inst✝ : Inhabited σ
n : ℕ
enc : Γ → Vector Bool n
dec : Vector Bool n → Γ
enc0 : enc default = Vector.replicate n false
M : Λ → Stmt₁
L R : ListBlank Γ
L✝ : Tape Bool
i : ℕ
IH : (Tape.move Dir.right)^[i] ((Tape.move Dir.left)^[i] L✝) = L✝
⊢ (Tape.move Dir.right)^[i + 1] ((Tape.move Dir.left)^[i + 1] L✝) = L✝

tactic: rw [iterate_succ_apply, iterate_succ_apply', Tape.move_left_right, IH]
state_before: case succ
Γ : Type u_1
inst✝² : Inhabited Γ
Λ : Type u_2
inst✝¹ : Inhabited Λ
σ : Type u_3
inst✝ : Inhabited σ
n : ℕ
enc : Γ → Vector Bool n
dec : Vector Bool n → Γ
enc0 : enc default = Vector.replicate n false
M : Λ → Stmt₁
L R : ListBlank Γ
L✝ : Tape Bool
i : ℕ
IH : (Tape.move Dir.right)^[i] ((Tape.move Dir.left)^[i] L✝) = L✝
⊢ (Tape.move Dir.right)^[i + 1] ((Tape.move Dir.left)^[i + 1] L✝) = L✝
state_after: no goals

tactic: refine (Eq.symm ?_).trans (this n _)
state_before: Γ : Type u_1
inst✝² : Inhabited Γ
Λ : Type u_2
inst✝¹ : Inhabited Λ
σ : Type u_3
inst✝ : Inhabited σ
n : ℕ
enc : Γ → Vector Bool n
dec : Vector Bool n → Γ
enc0 : enc default = Vector.replicate n false
M : Λ → Stmt₁
L R : ListBlank Γ
this : ∀ (i : ℕ) (L : Tape (?m.185124 i)), (Tape.move Dir.right)^[i] ((Tape.move Dir.left)^[i] L) = L
⊢ (Tape.move Dir.right)^[n] (trTape' enc0 L R) = trTape' enc0 (ListBlank.cons R.head L) R.tail
state_after: Γ : Type u_1
inst✝² : Inhabited Γ
Λ : Type u_2
inst✝¹ : Inhabited Λ
σ : Type u_3
inst✝ : Inhabited σ
n : ℕ
enc : Γ → Vector Bool n
dec : Vector Bool n → Γ
enc0 : enc default = Vector.replicate n false
M : Λ → Stmt₁
L R : ListBlank Γ
this : ∀ (i : ℕ) (L : Tape Bool), (Tape.move Dir.right)^[i] ((Tape.move Dir.left)^[i] L) = L
⊢ (Tape.move Dir.right)^[n] ((Tape.move Dir.left)^[n] (trTape' enc0 (ListBlank.cons R.head L) R.tail)) =
    (Tape.move Dir.right)^[n] (trTape' enc0 L R)

tactic: simp only [trTape'_move_left, ListBlank.cons_head_tail, ListBlank.head_cons,
  ListBlank.tail_cons]
state_before: Γ : Type u_1
inst✝² : Inhabited Γ
Λ : Type u_2
inst✝¹ : Inhabited Λ
σ : Type u_3
inst✝ : Inhabited σ
n : ℕ
enc : Γ → Vector Bool n
dec : Vector Bool n → Γ
enc0 : enc default = Vector.replicate n false
M : Λ → Stmt₁
L R : ListBlank Γ
this : ∀ (i : ℕ) (L : Tape Bool), (Tape.move Dir.right)^[i] ((Tape.move Dir.left)^[i] L) = L
⊢ (Tape.move Dir.right)^[n] ((Tape.move Dir.left)^[n] (trTape' enc0 (ListBlank.cons R.head L) R.tail)) =
    (Tape.move Dir.right)^[n] (trTape' enc0 L R)
state_after: no goals

tactic: rfl
state_before: case zero
Γ : Type u_1
inst✝² : Inhabited Γ
Λ : Type u_2
inst✝¹ : Inhabited Λ
σ : Type u_3
inst✝ : Inhabited σ
n : ℕ
enc : Γ → Vector Bool n
dec : Vector Bool n → Γ
enc0 : enc default = Vector.replicate n false
M : Λ → Stmt₁
L R : ListBlank Γ
L✝ : Tape Bool
⊢ (Tape.move Dir.right)^[0] ((Tape.move Dir.left)^[0] L✝) = L✝
state_after: no goals