apply IsDeduct.axiom_
case a
v : VarName
P : Formula
Δ : Set Formula
h1 : IsDeduct Δ (forall_ v P)
⊢ IsDeduct Δ ((forall_ v P).imp_ P)
case a.a
v : VarName
P : Formula
Δ : Set Formula
h1 : IsDeduct Δ (forall_ v P)
⊢ IsAxiom ((forall_ v P).imp_ P)