Theorem 19.43 1652

Description: Theorem 19.43 of [Margaris] p. 90. (Contributed by NM, 5-Aug-1993.) (Proof shortened by Mario Carneiro, 2-Feb-2015.)

Assertion

Ref	Expression
19.43	|- ( E. x ( ph \/ ps ) <-> ( E. x ph \/ E. x ps ) )

Proof of Theorem 19.43

Step	Hyp	Ref	Expression
1		hbe1 1519	. . . 4 |- ( E. x ph -> A. x E. x ph )
2		hbe1 1519	. . . 4 |- ( E. x ps -> A. x E. x ps )
3	1, 2	hbor 1570	. . 3 |- ( ( E. x ph \/ E. x ps ) -> A. x ( E. x ph \/ E. x ps ) )
4		19.8a 1614	. . . 4 |- ( ph -> E. x ph )
5		19.8a 1614	. . . 4 |- ( ps -> E. x ps )
6	4, 5	orim12i 761	. . 3 |- ( ( ph \/ ps ) -> ( E. x ph \/ E. x ps ) )
7	3, 6	exlimih 1617	. 2 |- ( E. x ( ph \/ ps ) -> ( E. x ph \/ E. x ps ) )
8		orc 714	. . . 4 |- ( ph -> ( ph \/ ps ) )
9	8	eximi 1624	. . 3 |- ( E. x ph -> E. x ( ph \/ ps ) )
10		olc 713	. . . 4 |- ( ps -> ( ph \/ ps ) )
11	10	eximi 1624	. . 3 |- ( E. x ps -> E. x ( ph \/ ps ) )
12	9, 11	jaoi 718	. 2 |- ( ( E. x ph \/ E. x ps ) -> E. x ( ph \/ ps ) )
13	7, 12	impbii 126	1 |- ( E. x ( ph \/ ps ) <-> ( E. x ph \/ E. x ps ) )

Syntax hints:   <-> wb 105   \/ wo 710   E.wex 1516

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 711  ax-5 1471  ax-gen 1473  ax-ie1 1517  ax-ie2 1518  ax-4 1534  ax-ial 1558

This theorem depends on definitions:  df-bi 117

This theorem is referenced by:  19.44  1706  19.45  1707  19.34  1708  sborv  1915  r19.43  2666  rexun  3361  unipr  3878  uniun  3883  unopab  4139  dmun  4904  coundi  5203  coundir  5204