simp only [Holds]
Δ : List Formula
F : Formula
X : PredName
xs ys : List VarName
ih_1 : xs.length = ys.length
D : Type
I : Interpretation D
V : VarAssignment D
E : Env
a✝ : ∀ H ∈ [], Holds D I V E H
⊢ Holds D I V E ((List.foldr and_ true_ (List.zipWith eq_ xs ys)).imp_ ((pred_var_ X xs).iff_ (pred_var_ X ys)))
Δ : List Formula
F : Formula
X : PredName
xs ys : List VarName
ih_1 : xs.length = ys.length
D : Type
I : Interpretation D
V : VarAssignment D
E : Env
a✝ : ∀ H ∈ [], Holds D I V E H
⊢ Holds D I V E (List.foldr and_ true_ (List.zipWith eq_ xs ys)) →
    (I.pred_var_ X (List.map V xs) ↔ I.pred_var_ X (List.map V ys))