apply IsDeduct.axiom_
case h3
P Q : Formula
v : VarName
h1 : ¬isFreeIn v P
⊢ IsDeduct ∅ ((forall_ v (P.imp_ Q)).imp_ ((forall_ v P).imp_ (forall_ v Q)))
case h3.a
P Q : Formula
v : VarName
h1 : ¬isFreeIn v P
⊢ IsAxiom ((forall_ v (P.imp_ Q)).imp_ ((forall_ v P).imp_ (forall_ v Q)))