contradiction
Δ : List Formula
F phi : Formula
D : Type
I : Interpretation D
V : VarAssignment D
E : Env
a✝ : ∀ H ∈ [], Holds D I V E H
a2 : Holds D I V E phi
d : D
v' : VarName
a1 : isFreeIn v' phi
ih : ¬isFreeIn v' phi
⊢ d = V v'
no goals