Theorem: LO.FirstOrder.Rew.shift_comp_substs1 (Logic/FirstOrder/Basic/Syntax/Rew.lean)

State before:
L : Language
L' : Language
L₁ : Language
L₂ : Language
L₃ : Language
ξ : Type u_1
ξ' : Type u_2
ξ₁ : Type u_3
ξ₂ : Type u_4
ξ₃ : Type u_5
n n₁ n₂ n₃ : ℕ
ω : Rew L ξ₁ n₁ ξ₂ n₂
t : SyntacticSemiterm L n₂
⊢ Rew.comp shift (substs ![t]) = (substs ![shift t]).comp shift
Tactic:
ext x <;> simp[comp_app]
State after:
no goals