Theorem: LO.FirstOrder.Derivation.CutFree.cast (Logic/FirstOrder/Basic/Calculus.lean)

State before:
L : Language
Δ✝ Δ₁ Δ₂ Γ✝ : Sequent L
p q r : SyntacticFormula L
Δ Γ : Sequent L
e : Δ = Γ
d :  ⊢¹ Δ
⊢ CutFree (Derivation.cast d e) ↔ CutFree d
Tactic:
rcases e with ⟨rfl⟩
State after:
case refl
L : Language
Δ✝ Δ₁ Δ₂ Γ : Sequent L
p q r : SyntacticFormula L
Δ : Sequent L
d :  ⊢¹ Δ
⊢ CutFree (Derivation.cast d ⋯) ↔ CutFree d

State before:
case refl
L : Language
Δ✝ Δ₁ Δ₂ Γ : Sequent L
p q r : SyntacticFormula L
Δ : Sequent L
d :  ⊢¹ Δ
⊢ CutFree (Derivation.cast d ⋯) ↔ CutFree d
Tactic:
simp
State after:
no goals