Theorem exisym1

Description: A symmetry with E. .

See negsym1 for more information. (Contributed by Anthony Hart, 4-Sep-2011)

	Ref	Expression
Assertion	exisym1	|- ( E. x E. x F. -> E. x ph )

Proof

Step	Hyp	Ref	Expression
1		nfe1	|- F/ x E. x ph
2		falim	|- ( F. -> ph )
3	2	eximi	|- ( E. x F. -> E. x ph )
4	1 3	exlimi	|- ( E. x E. x F. -> E. x ph )