Theorem axie1

Description: The setvar x is not free in E. x ph (intuitionistic logic axiom ax-ie1). (Contributed by Jim Kingdon, 31-Dec-2017) (New usage is discouraged.)

	Ref	Expression
Assertion	axie1	|- ( E. x ph -> A. x E. x ph )

Proof

Step	Hyp	Ref	Expression
1		hbe1	|- ( E. x ph -> A. x E. x ph )