case prop_1_ phi psi =>
  intro D I V E _
  simp only [Holds]
  tauto
Δ : List Formula
F phi psi : Formula
⊢ ∀ (D : Type) (I : Interpretation D) (V : VarAssignment D) (E : Env),
    (∀ H ∈ [], Holds D I V E H) → Holds D I V E (phi.imp_ (psi.imp_ phi))
no goals