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Theorem 2rexbii 2350
Description: Inference adding two restricted existential quantifiers to both sides of an equivalence. (Contributed by NM, 11-Nov-1995.)
Hypothesis
Ref Expression
ralbii.1  |-  ( ph  <->  ps )
Assertion
Ref Expression
2rexbii  |-  ( E. x  e.  A  E. y  e.  B  ph  <->  E. x  e.  A  E. y  e.  B  ps )

Proof of Theorem 2rexbii
StepHypRef Expression
1 ralbii.1 . . 3  |-  ( ph  <->  ps )
21rexbii 2348 . 2  |-  ( E. y  e.  B  ph  <->  E. y  e.  B  ps )
32rexbii 2348 1  |-  ( E. x  e.  A  E. y  e.  B  ph  <->  E. x  e.  A  E. y  e.  B  ps )
Colors of variables: wff set class
Syntax hints:    <-> wb 102   E.wrex 2324
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 103  ax-ia2 104  ax-ia3 105  ax-5 1352  ax-gen 1354  ax-ie1 1398  ax-ie2 1399  ax-4 1416  ax-17 1435  ax-ial 1443
This theorem depends on definitions:  df-bi 114  df-tru 1262  df-nf 1366  df-rex 2329
This theorem is referenced by:  3reeanv  2497  4fvwrd4  9099
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