intro a1
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))
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
a1 : 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)