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Theorem riota2 5720
Description: This theorem shows a condition that allows us to represent a descriptor with a class expression  B. (Contributed by NM, 23-Aug-2011.) (Revised by Mario Carneiro, 10-Dec-2016.)
Hypothesis
Ref Expression
riota2.1  |-  ( x  =  B  ->  ( ph 
<->  ps ) )
Assertion
Ref Expression
riota2  |-  ( ( B  e.  A  /\  E! x  e.  A  ph )  ->  ( ps  <->  (
iota_ x  e.  A  ph )  =  B ) )
Distinct variable groups:    ps, x    x, A    x, B
Allowed substitution hint:    ph( x)

Proof of Theorem riota2
StepHypRef Expression
1 nfcv 2258 . 2  |-  F/_ x B
2 nfv 1493 . 2  |-  F/ x ps
3 riota2.1 . 2  |-  ( x  =  B  ->  ( ph 
<->  ps ) )
41, 2, 3riota2f 5719 1  |-  ( ( B  e.  A  /\  E! x  e.  A  ph )  ->  ( ps  <->  (
iota_ x  e.  A  ph )  =  B ) )
Colors of variables: wff set class
Syntax hints:    -> wi 4    /\ wa 103    <-> wb 104    = wceq 1316    e. wcel 1465   E!wreu 2395   iota_crio 5697
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 683  ax-5 1408  ax-7 1409  ax-gen 1410  ax-ie1 1454  ax-ie2 1455  ax-8 1467  ax-10 1468  ax-11 1469  ax-i12 1470  ax-bndl 1471  ax-4 1472  ax-17 1491  ax-i9 1495  ax-ial 1499  ax-i5r 1500  ax-ext 2099
This theorem depends on definitions:  df-bi 116  df-3an 949  df-tru 1319  df-nf 1422  df-sb 1721  df-eu 1980  df-clab 2104  df-cleq 2110  df-clel 2113  df-nfc 2247  df-rex 2399  df-reu 2400  df-v 2662  df-sbc 2883  df-un 3045  df-sn 3503  df-pr 3504  df-uni 3707  df-iota 5058  df-riota 5698
This theorem is referenced by:  eqsupti  6851  prsrriota  7564  recriota  7666  axcaucvglemval  7673  subadd  7933  divmulap  8403  flqlelt  10017  flqbi  10031  remim  10600  resqrtcl  10769  rersqrtthlem  10770  divalgmod  11551  dfgcd3  11625  bezout  11626  oddpwdclemxy  11774  qnumdenbi  11797
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