simp
case h1.h1.h3
P Q : Formula
v : VarName
⊢ ∀ H ∈ {(forall_ v P.not_).not_, forall_ v (P.iff_ Q)}, ¬isFreeIn v H
case h1.h1.h3
P Q : Formula
v : VarName
⊢ ¬isFreeIn v (forall_ v P.not_).not_ ∧ ¬isFreeIn v (forall_ v (P.iff_ Q))