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Theorem rexcom4a 2761
Description: Specialized existential commutation lemma. (Contributed by Jeff Madsen, 1-Jun-2011.)
Assertion
Ref Expression
rexcom4a  |-  ( E. x E. y  e.  A  ( ph  /\  ps )  <->  E. y  e.  A  ( ph  /\  E. x ps ) )
Distinct variable groups:    x, A    x, y    ph, x
Allowed substitution hints:    ph( y)    ps( x, y)    A( y)

Proof of Theorem rexcom4a
StepHypRef Expression
1 rexcom4 2760 . 2  |-  ( E. y  e.  A  E. x ( ph  /\  ps )  <->  E. x E. y  e.  A  ( ph  /\ 
ps ) )
2 19.42v 1906 . . 3  |-  ( E. x ( ph  /\  ps )  <->  ( ph  /\  E. x ps ) )
32rexbii 2484 . 2  |-  ( E. y  e.  A  E. x ( ph  /\  ps )  <->  E. y  e.  A  ( ph  /\  E. x ps ) )
41, 3bitr3i 186 1  |-  ( E. x E. y  e.  A  ( ph  /\  ps )  <->  E. y  e.  A  ( ph  /\  E. x ps ) )
Colors of variables: wff set class
Syntax hints:    /\ wa 104    <-> wb 105   E.wex 1492   E.wrex 2456
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-tru 1356  df-nf 1461  df-sb 1763  df-clab 2164  df-cleq 2170  df-clel 2173  df-nfc 2308  df-rex 2461  df-v 2739
This theorem is referenced by:  rexcom4b  2762
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