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Theorem ceqsexg 2785
Description: A representation of explicit substitution of a class for a variable, inferred from an implicit substitution hypothesis. (Contributed by NM, 11-Oct-2004.)
Hypotheses
Ref Expression
ceqsexg.1  |-  F/ x ps
ceqsexg.2  |-  ( x  =  A  ->  ( ph 
<->  ps ) )
Assertion
Ref Expression
ceqsexg  |-  ( A  e.  V  ->  ( E. x ( x  =  A  /\  ph )  <->  ps ) )
Distinct variable group:    x, A
Allowed substitution hints:    ph( x)    ps( x)    V( x)

Proof of Theorem ceqsexg
StepHypRef Expression
1 nfcv 2256 . 2  |-  F/_ x A
2 nfe1 1455 . . 3  |-  F/ x E. x ( x  =  A  /\  ph )
3 ceqsexg.1 . . 3  |-  F/ x ps
42, 3nfbi 1551 . 2  |-  F/ x
( E. x ( x  =  A  /\  ph )  <->  ps )
5 ceqex 2784 . . 3  |-  ( x  =  A  ->  ( ph 
<->  E. x ( x  =  A  /\  ph ) ) )
6 ceqsexg.2 . . 3  |-  ( x  =  A  ->  ( ph 
<->  ps ) )
75, 6bibi12d 234 . 2  |-  ( x  =  A  ->  (
( ph  <->  ph )  <->  ( E. x ( x  =  A  /\  ph )  <->  ps ) ) )
8 biid 170 . 2  |-  ( ph  <->  ph )
91, 4, 7, 8vtoclgf 2716 1  |-  ( A  e.  V  ->  ( E. x ( x  =  A  /\  ph )  <->  ps ) )
Colors of variables: wff set class
Syntax hints:    -> wi 4    /\ wa 103    <-> wb 104    = wceq 1314   F/wnf 1419   E.wex 1451    e. wcel 1463
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 681  ax-5 1406  ax-7 1407  ax-gen 1408  ax-ie1 1452  ax-ie2 1453  ax-8 1465  ax-10 1466  ax-11 1467  ax-i12 1468  ax-bndl 1469  ax-4 1470  ax-17 1489  ax-i9 1493  ax-ial 1497  ax-i5r 1498  ax-ext 2097
This theorem depends on definitions:  df-bi 116  df-tru 1317  df-nf 1420  df-sb 1719  df-clab 2102  df-cleq 2108  df-clel 2111  df-nfc 2245  df-v 2660
This theorem is referenced by:  ceqsexgv  2786
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