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Theorem rexxfr2d 4223
Description: Transfer universal quantification from a variable  x to another variable  y contained in expression  A. (Contributed by Mario Carneiro, 20-Aug-2014.) (Proof shortened by Mario Carneiro, 19-Nov-2016.)
Hypotheses
Ref Expression
ralxfr2d.1  |-  ( (
ph  /\  y  e.  C )  ->  A  e.  V )
ralxfr2d.2  |-  ( ph  ->  ( x  e.  B  <->  E. y  e.  C  x  =  A ) )
ralxfr2d.3  |-  ( (
ph  /\  x  =  A )  ->  ( ps 
<->  ch ) )
Assertion
Ref Expression
rexxfr2d  |-  ( ph  ->  ( E. x  e.  B  ps  <->  E. y  e.  C  ch )
)
Distinct variable groups:    x, A    x, y, B    x, C    ch, x    ph, x, y    ps, y
Allowed substitution hints:    ps( x)    ch( y)    A( y)    C( y)    V( x, y)

Proof of Theorem rexxfr2d
StepHypRef Expression
1 ralxfr2d.1 . . . 4  |-  ( (
ph  /\  y  e.  C )  ->  A  e.  V )
2 elisset 2614 . . . 4  |-  ( A  e.  V  ->  E. x  x  =  A )
31, 2syl 14 . . 3  |-  ( (
ph  /\  y  e.  C )  ->  E. x  x  =  A )
4 ralxfr2d.2 . . . . . . . 8  |-  ( ph  ->  ( x  e.  B  <->  E. y  e.  C  x  =  A ) )
54biimprd 156 . . . . . . 7  |-  ( ph  ->  ( E. y  e.  C  x  =  A  ->  x  e.  B
) )
6 r19.23v 2470 . . . . . . 7  |-  ( A. y  e.  C  (
x  =  A  ->  x  e.  B )  <->  ( E. y  e.  C  x  =  A  ->  x  e.  B ) )
75, 6sylibr 132 . . . . . 6  |-  ( ph  ->  A. y  e.  C  ( x  =  A  ->  x  e.  B ) )
87r19.21bi 2450 . . . . 5  |-  ( (
ph  /\  y  e.  C )  ->  (
x  =  A  ->  x  e.  B )
)
9 eleq1 2142 . . . . 5  |-  ( x  =  A  ->  (
x  e.  B  <->  A  e.  B ) )
108, 9mpbidi 149 . . . 4  |-  ( (
ph  /\  y  e.  C )  ->  (
x  =  A  ->  A  e.  B )
)
1110exlimdv 1741 . . 3  |-  ( (
ph  /\  y  e.  C )  ->  ( E. x  x  =  A  ->  A  e.  B
) )
123, 11mpd 13 . 2  |-  ( (
ph  /\  y  e.  C )  ->  A  e.  B )
134biimpa 290 . 2  |-  ( (
ph  /\  x  e.  B )  ->  E. y  e.  C  x  =  A )
14 ralxfr2d.3 . 2  |-  ( (
ph  /\  x  =  A )  ->  ( ps 
<->  ch ) )
1512, 13, 14rexxfrd 4221 1  |-  ( ph  ->  ( E. x  e.  B  ps  <->  E. y  e.  C  ch )
)
Colors of variables: wff set class
Syntax hints:    -> wi 4    /\ wa 102    <-> wb 103    = wceq 1285   E.wex 1422    e. wcel 1434   A.wral 2349   E.wrex 2350
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 104  ax-ia2 105  ax-ia3 106  ax-io 663  ax-5 1377  ax-7 1378  ax-gen 1379  ax-ie1 1423  ax-ie2 1424  ax-8 1436  ax-10 1437  ax-11 1438  ax-i12 1439  ax-bndl 1440  ax-4 1441  ax-17 1460  ax-i9 1464  ax-ial 1468  ax-i5r 1469  ax-ext 2064
This theorem depends on definitions:  df-bi 115  df-tru 1288  df-nf 1391  df-sb 1687  df-clab 2069  df-cleq 2075  df-clel 2078  df-nfc 2209  df-ral 2354  df-rex 2355  df-v 2604
This theorem is referenced by:  rexrn  5336  rexima  5426
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