Theorem axial

Description: The setvar x is not free in A. x ph (intuitionistic logic axiom ax-ial). (Contributed by Jim Kingdon, 31-Dec-2017) (New usage is discouraged.)

	Ref	Expression
Assertion	axial	$$⊢\forall x\phi \to \forall x\forall x\phi$$

Proof

Step	Hyp	Ref	Expression
1		hba1	$$⊢\forall x\phi \to \forall x\forall x\phi$$