Theorem 2eximi

Description: Inference adding two existential quantifiers to antecedent and consequent. (Contributed by NM, 3-Feb-2005)

	Ref	Expression
Hypothesis	eximi.1	|- ( ph -> ps )
Assertion	2eximi	|- ( E. x E. y ph -> E. x E. y ps )

Proof

Step	Hyp	Ref	Expression
1		eximi.1	|- ( ph -> ps )
2	1	eximi	|- ( E. y ph -> E. y ps )
3	2	eximi	|- ( E. x E. y ph -> E. x E. y ps )