. contrapose; simp [not_not]; apply provable_iff_insert_neg_not_Lconsistent.mp;
case mpr
α : Type u_1
inst✝² : DecidableEq α
inst✝¹ : Inhabited α
L : DeductionParameter α
inst✝ : L.Normal
T : Theory α
p : Formula α
⊢ (L)-Consistent insert (~p) T → T *⊬[L]! p
no goals