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Theorem iota2df 5556
Description: A condition that allows us to represent "the unique element such that  ph " with a class expression  A. (Contributed by NM, 30-Dec-2014.)
Hypotheses
Ref Expression
iota2df.1  |-  ( ph  ->  B  e.  V )
iota2df.2  |-  ( ph  ->  E! x ps )
iota2df.3  |-  ( (
ph  /\  x  =  B )  ->  ( ps 
<->  ch ) )
iota2df.4  |-  F/ x ph
iota2df.5  |-  ( ph  ->  F/ x ch )
iota2df.6  |-  ( ph  -> 
F/_ x B )
Assertion
Ref Expression
iota2df  |-  ( ph  ->  ( ch  <->  ( iota x ps )  =  B ) )

Proof of Theorem iota2df
StepHypRef Expression
1 iota2df.1 . 2  |-  ( ph  ->  B  e.  V )
2 iota2df.3 . . 3  |-  ( (
ph  /\  x  =  B )  ->  ( ps 
<->  ch ) )
3 simpr 459 . . . 4  |-  ( (
ph  /\  x  =  B )  ->  x  =  B )
43eqeq2d 2416 . . 3  |-  ( (
ph  /\  x  =  B )  ->  (
( iota x ps )  =  x  <->  ( iota x ps )  =  B
) )
52, 4bibi12d 319 . 2  |-  ( (
ph  /\  x  =  B )  ->  (
( ps  <->  ( iota x ps )  =  x )  <->  ( ch  <->  ( iota x ps )  =  B ) ) )
6 iota2df.2 . . 3  |-  ( ph  ->  E! x ps )
7 iota1 5546 . . 3  |-  ( E! x ps  ->  ( ps 
<->  ( iota x ps )  =  x ) )
86, 7syl 17 . 2  |-  ( ph  ->  ( ps  <->  ( iota x ps )  =  x ) )
9 iota2df.4 . 2  |-  F/ x ph
10 iota2df.6 . 2  |-  ( ph  -> 
F/_ x B )
11 iota2df.5 . . 3  |-  ( ph  ->  F/ x ch )
12 nfiota1 5534 . . . . 5  |-  F/_ x
( iota x ps )
1312a1i 11 . . . 4  |-  ( ph  -> 
F/_ x ( iota
x ps ) )
1413, 10nfeqd 2571 . . 3  |-  ( ph  ->  F/ x ( iota
x ps )  =  B )
1511, 14nfbid 1961 . 2  |-  ( ph  ->  F/ x ( ch  <->  ( iota x ps )  =  B ) )
161, 5, 8, 9, 10, 15vtocldf 3107 1  |-  ( ph  ->  ( ch  <->  ( iota x ps )  =  B ) )
Colors of variables: wff setvar class
Syntax hints:    -> wi 4    <-> wb 184    /\ wa 367    = wceq 1405   F/wnf 1637    e. wcel 1842   E!weu 2238   F/_wnfc 2550   iotacio 5530
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1639  ax-4 1652  ax-5 1725  ax-6 1771  ax-7 1814  ax-10 1861  ax-11 1866  ax-12 1878  ax-13 2026  ax-ext 2380
This theorem depends on definitions:  df-bi 185  df-or 368  df-an 369  df-3an 976  df-tru 1408  df-ex 1634  df-nf 1638  df-sb 1764  df-eu 2242  df-clab 2388  df-cleq 2394  df-clel 2397  df-nfc 2552  df-ral 2758  df-rex 2759  df-v 3060  df-sbc 3277  df-un 3418  df-sn 3972  df-pr 3974  df-uni 4191  df-iota 5532
This theorem is referenced by:  iota2d  5557  iota2  5558  riota2df  6259  opiota  6842
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