Theorem r19.44av 2649

Description: One direction of a restricted quantifier version of Theorem 19.44 of [Margaris] p. 90. The other direction doesn't hold when A is empty. (Contributed by NM, 2-Apr-2004.)

Assertion

Ref	Expression
r19.44av	|- ( E. x e. A ( ph \/ ps ) -> ( E. x e. A ph \/ ps ) )

Distinct variable group:   ps, x

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

Proof of Theorem r19.44av

Step	Hyp	Ref	Expression
1		r19.43 2648	. 2 |- ( E. x e. A ( ph \/ ps ) <-> ( E. x e. A ph \/ E. x e. A ps ) )
2		idd 21	. . . 4 |- ( x e. A -> ( ps -> ps ) )
3	2	rexlimiv 2601	. . 3 |- ( E. x e. A ps -> ps )
4	3	orim2i 762	. 2 |- ( ( E. x e. A ph \/ E. x e. A ps ) -> ( E. x e. A ph \/ ps ) )
5	1, 4	sylbi 121	1 |- ( E. x e. A ( ph \/ ps ) -> ( E. x e. A ph \/ ps ) )

Syntax hints:   -> wi 4   \/ wo 709   e. wcel 2160   E.wrex 2469

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-io 710  ax-5 1458  ax-gen 1460  ax-ie1 1504  ax-ie2 1505  ax-4 1521  ax-17 1537  ax-ial 1545  ax-i5r 1546

This theorem depends on definitions:  df-bi 117  df-nf 1472  df-ral 2473  df-rex 2474

This theorem is referenced by: (None)