Theorem eeorOLD

Description: Obsolete version of eeor as of 21-Nov-2024. (Contributed by NM, 8-Aug-1994) (Proof modification is discouraged.) (New usage is discouraged.)

	Ref	Expression
Hypotheses	eeor.1	|- F/ y ph
	eeor.2	|- F/ x ps
Assertion	eeorOLD	|- ( E. x E. y ( ph \/ ps ) <-> ( E. x ph \/ E. y ps ) )

Proof

Step	Hyp	Ref	Expression
1		eeor.1	|- F/ y ph
2		eeor.2	|- F/ x ps
3	1	19.45	|- ( E. y ( ph \/ ps ) <-> ( ph \/ E. y ps ) )
4	3	exbii	|- ( E. x E. y ( ph \/ ps ) <-> E. x ( ph \/ E. y ps ) )
5	2	nfex	|- F/ x E. y ps
6	5	19.44	|- ( E. x ( ph \/ E. y ps ) <-> ( E. x ph \/ E. y ps ) )
7	4 6	bitri	|- ( E. x E. y ( ph \/ ps ) <-> ( E. x ph \/ E. y ps ) )