Theorem cbvrmo 2656

Description: Change the bound variable of restricted "at most one" using implicit substitution. (Contributed by NM, 16-Jun-2017.)

Hypotheses

Ref	Expression
cbvral.1	|- F/ y ph
cbvral.2	|- F/ x ps
cbvral.3	|- ( x = y -> ( ph <-> ps ) )

Assertion

Ref	Expression
cbvrmo	|- ( E* x e. A ph <-> E* y e. A ps )

Distinct variable groups:   x, A   y, A

Allowed substitution hints:   ph( x, y)   ps( x, y)

Proof of Theorem cbvrmo

Step	Hyp	Ref	Expression
1		cbvral.1	. . . 4 |- F/ y ph
2		cbvral.2	. . . 4 |- F/ x ps
3		cbvral.3	. . . 4 |- ( x = y -> ( ph <-> ps ) )
4	1, 2, 3	cbvrex 2654	. . 3 |- ( E. x e. A ph <-> E. y e. A ps )
5	1, 2, 3	cbvreu 2655	. . 3 |- ( E! x e. A ph <-> E! y e. A ps )
6	4, 5	imbi12i 238	. 2 |- ( ( E. x e. A ph -> E! x e. A ph ) <-> ( E. y e. A ps -> E! y e. A ps ) )
7		rmo5 2649	. 2 |- ( E* x e. A ph <-> ( E. x e. A ph -> E! x e. A ph ) )
8		rmo5 2649	. 2 |- ( E* y e. A ps <-> ( E. y e. A ps -> E! y e. A ps ) )
9	6, 7, 8	3bitr4i 211	1 |- ( E* x e. A ph <-> E* y e. A ps )

Syntax hints:   -> wi 4   <-> wb 104   F/wnf 1437   E.wrex 2418   E!wreu 2419   E*wrmo 2420

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 1424  ax-7 1425  ax-gen 1426  ax-ie1 1470  ax-ie2 1471  ax-8 1483  ax-10 1484  ax-11 1485  ax-i12 1486  ax-bndl 1487  ax-4 1488  ax-17 1507  ax-i9 1511  ax-ial 1515  ax-i5r 1516  ax-ext 2122

This theorem depends on definitions:  df-bi 116  df-tru 1335  df-nf 1438  df-sb 1737  df-eu 2003  df-mo 2004  df-cleq 2133  df-clel 2136  df-nfc 2271  df-rex 2423  df-reu 2424  df-rmo 2425

This theorem is referenced by:  cbvrmov  2660  cbvdisj  3924