Theorem r19.45av 2626

Description: Restricted version of one direction of Theorem 19.45 of [Margaris] p. 90. (The other direction doesn't hold when A is empty.) (Contributed by NM, 2-Apr-2004.)

Assertion

Ref	Expression
r19.45av	|- ( E. x e. A ( ph \/ ps ) -> ( ph \/ E. x e. A ps ) )

Distinct variable group:   ph, x

Allowed substitution hints:   ps( x)   A( x)

Proof of Theorem r19.45av

Step	Hyp	Ref	Expression
1		r19.43 2624	. 2 |- ( E. x e. A ( ph \/ ps ) <-> ( E. x e. A ph \/ E. x e. A ps ) )
2		idd 21	. . . 4 |- ( x e. A -> ( ph -> ph ) )
3	2	rexlimiv 2577	. . 3 |- ( E. x e. A ph -> ph )
4	3	orim1i 750	. 2 |- ( ( E. x e. A ph \/ E. x e. A ps ) -> ( ph \/ E. x e. A ps ) )
5	1, 4	sylbi 120	1 |- ( E. x e. A ( ph \/ ps ) -> ( ph \/ E. x e. A ps ) )

Syntax hints:   -> wi 4   \/ wo 698   e. wcel 2136   E.wrex 2445

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-io 699  ax-5 1435  ax-gen 1437  ax-ie1 1481  ax-ie2 1482  ax-4 1498  ax-17 1514  ax-ial 1522  ax-i5r 1523

This theorem depends on definitions:  df-bi 116  df-nf 1449  df-ral 2449  df-rex 2450

This theorem is referenced by: (None)