Theorem axi4

Description: Specialization (intuitionistic logic axiom ax-4). This is just sp by another name. (Contributed by Jim Kingdon, 31-Dec-2017) (New usage is discouraged.)

	Ref	Expression
Assertion	axi4	|- ( A. x ph -> ph )

Proof

Step	Hyp	Ref	Expression
1		sp	|- ( A. x ph -> ph )