-- Mathlib/Computability/PostTuringMachine.lean
theorem tr_supports {S : Finset Λ} (ss : TM1.Supports M S) :
    TM0.Supports (tr M) ↑(trStmts M S)

Proof state:
case right.mk.some.mk.some.branch
Γ : Type u_1
Λ : Type u_2
inst✝² : Inhabited Λ
σ : Type u_3
inst✝¹ : Inhabited σ
M : Λ → TM1.Stmt Γ Λ σ
inst✝ : Fintype σ
S : Finset Λ
ss : TM1.Supports M S
a : Γ
s : TM0.Stmt Γ
v' : σ
val✝ : TM1.Stmt Γ Λ σ
p : Γ → σ → Bool
q₁ q₂ : TM1.Stmt Γ Λ σ
IH₁ :
  ∀ (v : σ),
    some q₁ ∈ TM1.stmts M S →
      some (trAux M a q₁ v) = some ((some val✝, v'), s) → TM1.SupportsStmt S q₁ → some val✝ ∈ TM1.stmts M S
IH₂ :
  ∀ (v : σ),
    some q₂ ∈ TM1.stmts M S →
      some (trAux M a q₂ v) = some ((some val✝, v'), s) → TM1.SupportsStmt S q₂ → some val✝ ∈ TM1.stmts M S
v : σ
h₂ : some (TM1.Stmt.branch p q₁ q₂) ∈ TM1.stmts M S
h₁ : some (trAux M a (TM1.Stmt.branch p q₁ q₂) v) = some ((some val✝, v'), s)
hs : TM1.SupportsStmt S (TM1.Stmt.branch p q₁ q₂)
⊢ some val✝ ∈ TM1.stmts M S

Tactic:
cases h : p a v <;> rw [trAux, h] at h₁

Result:
case right.mk.some.mk.some.branch.false
Γ : Type u_1
Λ : Type u_2
inst✝² : Inhabited Λ
σ : Type u_3
inst✝¹ : Inhabited σ
M : Λ → TM1.Stmt Γ Λ σ
inst✝ : Fintype σ
S : Finset Λ
ss : TM1.Supports M S
a : Γ
s : TM0.Stmt Γ
v' : σ
val✝ : TM1.Stmt Γ Λ σ
p : Γ → σ → Bool
q₁ q₂ : TM1.Stmt Γ Λ σ
IH₁ :
  ∀ (v : σ),
    some q₁ ∈ TM1.stmts M S →
      some (trAux M a q₁ v) = some ((some val✝, v'), s) → TM1.SupportsStmt S q₁ → some val✝ ∈ TM1.stmts M S
IH₂ :
  ∀ (v : σ),
    some q₂ ∈ TM1.stmts M S →
      some (trAux M a q₂ v) = some ((some val✝, v'), s) → TM1.SupportsStmt S q₂ → some val✝ ∈ TM1.stmts M S
v : σ
h₂ : some (TM1.Stmt.branch p q₁ q₂) ∈ TM1.stmts M S
h₁ : some (bif false then trAux M a q₁ v else trAux M a q₂ v) = some ((some val✝, v'), s)
hs : TM1.SupportsStmt S (TM1.Stmt.branch p q₁ q₂)
h : p a v = false
⊢ some val✝ ∈ TM1.stmts M S

case right.mk.some.mk.some.branch.true
Γ : Type u_1
Λ : Type u_2
inst✝² : Inhabited Λ
σ : Type u_3
inst✝¹ : Inhabited σ
M : Λ → TM1.Stmt Γ Λ σ
inst✝ : Fintype σ
S : Finset Λ
ss : TM1.Supports M S
a : Γ
s : TM0.Stmt Γ
v' : σ
val✝ : TM1.Stmt Γ Λ σ
p : Γ → σ → Bool
q₁ q₂ : TM1.Stmt Γ Λ σ
IH₁ :
  ∀ (v : σ),
    some q₁ ∈ TM1.stmts M S →
      some (trAux M a q₁ v) = some ((some val✝, v'), s) → TM1.SupportsStmt S q₁ → some val✝ ∈ TM1.stmts M S
IH₂ :
  ∀ (v : σ),
    some q₂ ∈ TM1.stmts M S →
      some (trAux M a q₂ v) = some ((some val✝, v'), s) → TM1.SupportsStmt S q₂ → some val✝ ∈ TM1.stmts M S
v : σ
h₂ : some (TM1.Stmt.branch p q₁ q₂) ∈ TM1.stmts M S
h₁ : some (bif true then trAux M a q₁ v else trAux M a q₂ v) = some ((some val✝, v'), s)
hs : TM1.SupportsStmt S (TM1.Stmt.branch p q₁ q₂)
h : p a v = true
⊢ some val✝ ∈ TM1.stmts M S

Proof state:
case right
Γ : Type u_1
Λ : Type u_2
inst✝² : Inhabited Λ
σ : Type u_3
inst✝¹ : Inhabited σ
M : Λ → TM1.Stmt Γ Λ σ
inst✝ : Fintype σ
S : Finset Λ
ss : TM1.Supports M S
q : Λ' M
a : Γ
q' : Λ' M
s : TM0.Stmt Γ
h₁ : (q', s) ∈ tr M q a
h₂ : q ∈ ↑(trStmts M S)
⊢ q' ∈ ↑(trStmts M S)

Tactic:
rcases q with ⟨_ | q, v⟩

Result:
case right.mk.none
Γ : Type u_1
Λ : Type u_2
inst✝² : Inhabited Λ
σ : Type u_3
inst✝¹ : Inhabited σ
M : Λ → TM1.Stmt Γ Λ σ
inst✝ : Fintype σ
S : Finset Λ
ss : TM1.Supports M S
a : Γ
q' : Λ' M
s : TM0.Stmt Γ
v : σ
h₁ : (q', s) ∈ tr M (none, v) a
h₂ : (none, v) ∈ ↑(trStmts M S)
⊢ q' ∈ ↑(trStmts M S)

case right.mk.some
Γ : Type u_1
Λ : Type u_2
inst✝² : Inhabited Λ
σ : Type u_3
inst✝¹ : Inhabited σ
M : Λ → TM1.Stmt Γ Λ σ
inst✝ : Fintype σ
S : Finset Λ
ss : TM1.Supports M S
a : Γ
q' : Λ' M
s : TM0.Stmt Γ
v : σ
q : TM1.Stmt Γ Λ σ
h₁ : (q', s) ∈ tr M (some q, v) a
h₂ : (some q, v) ∈ ↑(trStmts M S)
⊢ q' ∈ ↑(trStmts M S)

Proof state:
case right.mk.some.mk
Γ : Type u_1
Λ : Type u_2
inst✝² : Inhabited Λ
σ : Type u_3
inst✝¹ : Inhabited σ
M : Λ → TM1.Stmt Γ Λ σ
inst✝ : Fintype σ
S : Finset Λ
ss : TM1.Supports M S
a : Γ
s : TM0.Stmt Γ
v : σ
q : TM1.Stmt Γ Λ σ
q' : Option (TM1.Stmt Γ Λ σ)
v' : σ
h₁ : ((q', v'), s) ∈ tr M (some q, v) a
h₂ : (some q, v) ∈ TM1.stmts M S ×ˢ Finset.univ
⊢ (q', v') ∈ TM1.stmts M S ×ˢ Finset.univ

Tactic:
rw [Finset.mem_product] at h₂ ⊢

Result:
case right.mk.some.mk
Γ : Type u_1
Λ : Type u_2
inst✝² : Inhabited Λ
σ : Type u_3
inst✝¹ : Inhabited σ
M : Λ → TM1.Stmt Γ Λ σ
inst✝ : Fintype σ
S : Finset Λ
ss : TM1.Supports M S
a : Γ
s : TM0.Stmt Γ
v : σ
q : TM1.Stmt Γ Λ σ
q' : Option (TM1.Stmt Γ Λ σ)
v' : σ
h₁ : ((q', v'), s) ∈ tr M (some q, v) a
h₂ : (some q, v).1 ∈ TM1.stmts M S ∧ (some q, v).2 ∈ Finset.univ
⊢ (q', v').1 ∈ TM1.stmts M S ∧ (q', v').2 ∈ Finset.univ

Proof state:
case right
Γ : Type u_1
Λ : Type u_2
inst✝² : Inhabited Λ
σ : Type u_3
inst✝¹ : Inhabited σ
M : Λ → TM1.Stmt Γ Λ σ
inst✝ : Fintype σ
S : Finset Λ
ss : TM1.Supports M S
⊢ ∀ {q : Λ' M} {a : Γ} {q' : Λ' M} {s : TM0.Stmt Γ}, (q', s) ∈ tr M q a → q ∈ ↑(trStmts M S) → q' ∈ ↑(trStmts M S)

Tactic:
intro q a q' s h₁ h₂

Result:
case right
Γ : Type u_1
Λ : Type u_2
inst✝² : Inhabited Λ
σ : Type u_3
inst✝¹ : Inhabited σ
M : Λ → TM1.Stmt Γ Λ σ
inst✝ : Fintype σ
S : Finset Λ
ss : TM1.Supports M S
q : Λ' M
a : Γ
q' : Λ' M
s : TM0.Stmt Γ
h₁ : (q', s) ∈ tr M q a
h₂ : q ∈ ↑(trStmts M S)
⊢ q' ∈ ↑(trStmts M S)

Proof state:
case right.mk.some.mk.some.branch.false
Γ : Type u_1
Λ : Type u_2
inst✝² : Inhabited Λ
σ : Type u_3
inst✝¹ : Inhabited σ
M : Λ → TM1.Stmt Γ Λ σ
inst✝ : Fintype σ
S : Finset Λ
ss : TM1.Supports M S
a : Γ
s : TM0.Stmt Γ
v' : σ
val✝ : TM1.Stmt Γ Λ σ
p : Γ → σ → Bool
q₁ q₂ : TM1.Stmt Γ Λ σ
IH₁ :
  ∀ (v : σ),
    some q₁ ∈ TM1.stmts M S →
      some (trAux M a q₁ v) = some ((some val✝, v'), s) → TM1.SupportsStmt S q₁ → some val✝ ∈ TM1.stmts M S
IH₂ :
  ∀ (v : σ),
    some q₂ ∈ TM1.stmts M S →
      some (trAux M a q₂ v) = some ((some val✝, v'), s) → TM1.SupportsStmt S q₂ → some val✝ ∈ TM1.stmts M S
v : σ
h₂ : some (TM1.Stmt.branch p q₁ q₂) ∈ TM1.stmts M S
h₁ : some (bif false then trAux M a q₁ v else trAux M a q₂ v) = some ((some val✝, v'), s)
hs : TM1.SupportsStmt S (TM1.Stmt.branch p q₁ q₂)
h : p a v = false
⊢ q₂ ∈ TM1.stmts₁ (TM1.Stmt.branch p q₁ q₂)

Tactic:
unfold TM1.stmts₁

Result:
case right.mk.some.mk.some.branch.false
Γ : Type u_1
Λ : Type u_2
inst✝² : Inhabited Λ
σ : Type u_3
inst✝¹ : Inhabited σ
M : Λ → TM1.Stmt Γ Λ σ
inst✝ : Fintype σ
S : Finset Λ
ss : TM1.Supports M S
a : Γ
s : TM0.Stmt Γ
v' : σ
val✝ : TM1.Stmt Γ Λ σ
p : Γ → σ → Bool
q₁ q₂ : TM1.Stmt Γ Λ σ
IH₁ :
  ∀ (v : σ),
    some q₁ ∈ TM1.stmts M S →
      some (trAux M a q₁ v) = some ((some val✝, v'), s) → TM1.SupportsStmt S q₁ → some val✝ ∈ TM1.stmts M S
IH₂ :
  ∀ (v : σ),
    some q₂ ∈ TM1.stmts M S →
      some (trAux M a q₂ v) = some ((some val✝, v'), s) → TM1.SupportsStmt S q₂ → some val✝ ∈ TM1.stmts M S
v : σ
h₂ : some (TM1.Stmt.branch p q₁ q₂) ∈ TM1.stmts M S
h₁ : some (bif false then trAux M a q₁ v else trAux M a q₂ v) = some ((some val✝, v'), s)
hs : TM1.SupportsStmt S (TM1.Stmt.branch p q₁ q₂)
h : p a v = false
⊢ q₂ ∈ insert (TM1.Stmt.branch p q₁ q₂) (TM1.stmts₁ q₁ ∪ TM1.stmts₁ q₂)

Proof state:
case left
Γ : Type u_1
Λ : Type u_2
inst✝² : Inhabited Λ
σ : Type u_3
inst✝¹ : Inhabited σ
M : Λ → TM1.Stmt Γ Λ σ
inst✝ : Fintype σ
S : Finset Λ
ss : TM1.Supports M S
⊢ default ∈ ↑(trStmts M S)

Tactic:
apply Finset.mem_product.2

Result:
case left
Γ : Type u_1
Λ : Type u_2
inst✝² : Inhabited Λ
σ : Type u_3
inst✝¹ : Inhabited σ
M : Λ → TM1.Stmt Γ Λ σ
inst✝ : Fintype σ
S : Finset Λ
ss : TM1.Supports M S
⊢ default.1 ∈ TM1.stmts M S ∧ default.2 ∈ Finset.univ