Theorem rmo5 2681

Description: Restricted "at most one" in term of uniqueness. (Contributed by NM, 16-Jun-2017.)

Assertion

Ref	Expression
rmo5	|- ( E* x e. A ph <-> ( E. x e. A ph -> E! x e. A ph ) )

Proof of Theorem rmo5

Step	Hyp	Ref	Expression
1		df-mo 2018	. 2 |- ( E* x ( x e. A /\ ph ) <-> ( E. x ( x e. A /\ ph ) -> E! x ( x e. A /\ ph ) ) )
2		df-rmo 2452	. 2 |- ( E* x e. A ph <-> E* x ( x e. A /\ ph ) )
3		df-rex 2450	. . 3 |- ( E. x e. A ph <-> E. x ( x e. A /\ ph ) )
4		df-reu 2451	. . 3 |- ( E! x e. A ph <-> E! x ( x e. A /\ ph ) )
5	3, 4	imbi12i 238	. 2 |- ( ( E. x e. A ph -> E! x e. A ph ) <-> ( E. x ( x e. A /\ ph ) -> E! x ( x e. A /\ ph ) ) )
6	1, 2, 5	3bitr4i 211	1 |- ( E* x e. A ph <-> ( E. x e. A ph -> E! x e. A ph ) )

Syntax hints:   -> wi 4   /\ wa 103   <-> wb 104   E.wex 1480   E!weu 2014   E*wmo 2015   e. wcel 2136   E.wrex 2445   E!wreu 2446   E*wrmo 2447

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 105  ax-ia2 106  ax-ia3 107

This theorem depends on definitions:  df-bi 116  df-mo 2018  df-rex 2450  df-reu 2451  df-rmo 2452

This theorem is referenced by:  nrexrmo  2682  cbvrmo  2691  bdrmo  13738