Module: Mathlib.Computability.TuringMachine.ToPartrec

Goal state before:
pp: case cons₁.refine_1
fs : Code
as : List ℕ
k : Cont
a_ih✝ :
  ∀ (v : List ℕ) (s : Option Γ'),
    ∃ b₂,
      TrCfg (stepRet k v) b₂ ∧
        Reaches₁ (TM2.step tr) { l := some (Λ'.ret (trCont k)), var := s, stk := elim (trList v) [] [] (trContStack k) }
          b₂
v : List ℕ
s : Option Γ'
s' : Cfg'
h₁ : TrCfg (stepNormal fs (Cont.cons₂ v k) as) s'
h₂ :
  Reaches₁ (TM2.step tr)
    { l := some (trNormal fs (trCont (Cont.cons₂ v k))), var := none,
      stk := elim (trList as) [] [] (trContStack (Cont.cons₂ v k)) }
    s'
⊢ elim (trList v) [] [] (trContStack (Cont.cons₁ fs as k)) rev = []

pp: case cons₁.refine_2
fs : Code
as : List ℕ
k : Cont
a_ih✝ :
  ∀ (v : List ℕ) (s : Option Γ'),
    ∃ b₂,
      TrCfg (stepRet k v) b₂ ∧
        Reaches₁ (TM2.step tr) { l := some (Λ'.ret (trCont k)), var := s, stk := elim (trList v) [] [] (trContStack k) }
          b₂
v : List ℕ
s : Option Γ'
s' : Cfg'
h₁ : TrCfg (stepNormal fs (Cont.cons₂ v k) as) s'
h₂ :
  Reaches₁ (TM2.step tr)
    { l := some (trNormal fs (trCont (Cont.cons₂ v k))), var := none,
      stk := elim (trList as) [] [] (trContStack (Cont.cons₂ v k)) }
    s'
⊢ TransGen (fun a b ↦ b ∈ TM2.step tr a)
    {
      l :=
        some
          (move₂ (fun s ↦ decide (s = Γ'.consₗ)) stack main
            (move₂ (fun x ↦ false) aux stack (trNormal fs (trCont k).cons₂))),
      var := none,
      stk :=
        update (update (elim (trList v) [] [] (trContStack (Cont.cons₁ fs as k))) main (none.elim id List.cons [])) aux
          (elim (trList v) [] [] (trContStack (Cont.cons₁ fs as k)) main ++
            elim (trList v) [] [] (trContStack (Cont.cons₁ fs as k)) aux) }
    s'

Tactic:
;

Goal state after:
case cons₁.refine_1
fs : Code
as : List ℕ
k : Cont
a_ih✝ :
  ∀ (v : List ℕ) (s : Option Γ'),
    ∃ b₂,
      TrCfg (stepRet k v) b₂ ∧
        Reaches₁ (TM2.step tr) { l := some (Λ'.ret (trCont k)), var := s, stk := elim (trList v) [] [] (trContStack k) }
          b₂
v : List ℕ
s : Option Γ'
s' : Cfg'
h₁ : TrCfg (stepNormal fs (Cont.cons₂ v k) as) s'
h₂ :
  Reaches₁ (TM2.step tr)
    { l := some (trNormal fs (trCont (Cont.cons₂ v k))), var := none,
      stk := elim (trList as) [] [] (trContStack (Cont.cons₂ v k)) }
    s'
⊢ elim (trList v) [] [] (trContStack (Cont.cons₁ fs as k)) rev = []

case cons₁.refine_2
fs : Code
as : List ℕ
k : Cont
a_ih✝ :
  ∀ (v : List ℕ) (s : Option Γ'),
    ∃ b₂,
      TrCfg (stepRet k v) b₂ ∧
        Reaches₁ (TM2.step tr) { l := some (Λ'.ret (trCont k)), var := s, stk := elim (trList v) [] [] (trContStack k) }
          b₂
v : List ℕ
s : Option Γ'
s' : Cfg'
h₁ : TrCfg (stepNormal fs (Cont.cons₂ v k) as) s'
h₂ :
  Reaches₁ (TM2.step tr)
    { l := some (trNormal fs (trCont (Cont.cons₂ v k))), var := none,
      stk := elim (trList as) [] [] (trContStack (Cont.cons₂ v k)) }
    s'
⊢ TransGen (fun a b ↦ b ∈ TM2.step tr a)
    {
      l :=
        some
          (move₂ (fun s ↦ decide (s = Γ'.consₗ)) stack main
            (move₂ (fun x ↦ false) aux stack (trNormal fs (trCont k).cons₂))),
      var := none,
      stk :=
        update (update (elim (trList v) [] [] (trContStack (Cont.cons₁ fs as k))) main (none.elim id List.cons [])) aux
          (elim (trList v) [] [] (trContStack (Cont.cons₁ fs as k)) main ++
            elim (trList v) [] [] (trContStack (Cont.cons₁ fs as k)) aux) }
    s'