simp only [predVarSet] at h1
P : PredName
zs : List VarName
H phi : Formula
phi_ih : phi.predVarSet = ∅ → replace P zs H phi = phi
h1 : phi.not_.predVarSet = ∅
⊢ replace P zs H phi.not_ = phi.not_
P : PredName
zs : List VarName
H phi : Formula
phi_ih : phi.predVarSet = ∅ → replace P zs H phi = phi
h1 : phi.predVarSet = ∅
⊢ replace P zs H phi.not_ = phi.not_