Theorem rexxfr2d 4425

Description: Transfer universal quantification from a variable x to another variable y contained in expression A. (Contributed by Mario Carneiro, 20-Aug-2014.) (Proof shortened by Mario Carneiro, 19-Nov-2016.)

Hypotheses

Ref	Expression
ralxfr2d.1	|- ( ( ph /\ y e. C ) -> A e. V )
ralxfr2d.2	|- ( ph -> ( x e. B <-> E. y e. C x = A ) )
ralxfr2d.3	|- ( ( ph /\ x = A ) -> ( ps <-> ch ) )

Assertion

Ref	Expression
rexxfr2d	|- ( ph -> ( E. x e. B ps <-> E. y e. C ch ) )

Distinct variable groups:   x, A   x, y, B   x, C   ch, x   ph, x, y   ps, y

Allowed substitution hints:   ps( x)   ch( y)   A( y)   C( y)   V( x, y)

Proof of Theorem rexxfr2d

Step	Hyp	Ref	Expression
1		ralxfr2d.1	. . . 4 |- ( ( ph /\ y e. C ) -> A e. V )
2		elisset 2726	. . . 4 |- ( A e. V -> E. x x = A )
3	1, 2	syl 14	. . 3 |- ( ( ph /\ y e. C ) -> E. x x = A )
4		ralxfr2d.2	. . . . . . . 8 |- ( ph -> ( x e. B <-> E. y e. C x = A ) )
5	4	biimprd 157	. . . . . . 7 |- ( ph -> ( E. y e. C x = A -> x e. B ) )
6		r19.23v 2566	. . . . . . 7 |- ( A. y e. C ( x = A -> x e. B ) <-> ( E. y e. C x = A -> x e. B ) )
7	5, 6	sylibr 133	. . . . . 6 |- ( ph -> A. y e. C ( x = A -> x e. B ) )
8	7	r19.21bi 2545	. . . . 5 |- ( ( ph /\ y e. C ) -> ( x = A -> x e. B ) )
9		eleq1 2220	. . . . 5 |- ( x = A -> ( x e. B <-> A e. B ) )
10	8, 9	mpbidi 150	. . . 4 |- ( ( ph /\ y e. C ) -> ( x = A -> A e. B ) )
11	10	exlimdv 1799	. . 3 |- ( ( ph /\ y e. C ) -> ( E. x x = A -> A e. B ) )
12	3, 11	mpd 13	. 2 |- ( ( ph /\ y e. C ) -> A e. B )
13	4	biimpa 294	. 2 |- ( ( ph /\ x e. B ) -> E. y e. C x = A )
14		ralxfr2d.3	. 2 |- ( ( ph /\ x = A ) -> ( ps <-> ch ) )
15	12, 13, 14	rexxfrd 4423	1 |- ( ph -> ( E. x e. B ps <-> E. y e. C ch ) )

Syntax hints:   -> wi 4   /\ wa 103   <-> wb 104   = wceq 1335   E.wex 1472   e. wcel 2128   A.wral 2435   E.wrex 2436

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 1427  ax-7 1428  ax-gen 1429  ax-ie1 1473  ax-ie2 1474  ax-8 1484  ax-10 1485  ax-11 1486  ax-i12 1487  ax-bndl 1489  ax-4 1490  ax-17 1506  ax-i9 1510  ax-ial 1514  ax-i5r 1515  ax-ext 2139

This theorem depends on definitions:  df-bi 116  df-tru 1338  df-nf 1441  df-sb 1743  df-clab 2144  df-cleq 2150  df-clel 2153  df-nfc 2288  df-ral 2440  df-rex 2441  df-v 2714

This theorem is referenced by:  rexrn  5604  rexima  5705  cnptopresti  12649  cnptoprest  12650  txrest  12687