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Theorem riota2 5846
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 2319 . 2  |-  F/_ x B
2 nfv 1528 . 2  |-  F/ x ps
3 riota2.1 . 2  |-  ( x  =  B  ->  ( ph 
<->  ps ) )
41, 2, 3riota2f 5845 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 104    <-> wb 105    = wceq 1353    e. wcel 2148   E!wreu 2457   iota_crio 5823
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-io 709  ax-5 1447  ax-7 1448  ax-gen 1449  ax-ie1 1493  ax-ie2 1494  ax-8 1504  ax-10 1505  ax-11 1506  ax-i12 1507  ax-bndl 1509  ax-4 1510  ax-17 1526  ax-i9 1530  ax-ial 1534  ax-i5r 1535  ax-ext 2159
This theorem depends on definitions:  df-bi 117  df-3an 980  df-tru 1356  df-nf 1461  df-sb 1763  df-eu 2029  df-clab 2164  df-cleq 2170  df-clel 2173  df-nfc 2308  df-rex 2461  df-reu 2462  df-v 2739  df-sbc 2963  df-un 3133  df-sn 3597  df-pr 3598  df-uni 3808  df-iota 5173  df-riota 5824
This theorem is referenced by:  eqsupti  6988  prsrriota  7765  recriota  7867  axcaucvglemval  7874  subadd  8137  divmulap  8608  flqlelt  10249  flqbi  10263  remim  10840  resqrtcl  11009  rersqrtthlem  11010  divalgmod  11902  dfgcd3  11981  bezout  11982  oddpwdclemxy  12139  qnumdenbi  12162  ismgmid  12675  isgrpinv  12803
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