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Theorem r19.9rmv 3341
Description: Restricted quantification of wff not containing quantified variable. (Contributed by Jim Kingdon, 5-Aug-2018.)
Assertion
Ref Expression
r19.9rmv  |-  ( E. y  y  e.  A  ->  ( ph  <->  E. x  e.  A  ph ) )
Distinct variable groups:    x, A    y, A    ph, x
Allowed substitution hint:    ph( y)

Proof of Theorem r19.9rmv
Dummy variable  a is distinct from all other variables.
StepHypRef Expression
1 eleq1 2116 . . 3  |-  ( a  =  y  ->  (
a  e.  A  <->  y  e.  A ) )
21cbvexv 1811 . 2  |-  ( E. a  a  e.  A  <->  E. y  y  e.  A
)
3 eleq1 2116 . . . 4  |-  ( a  =  x  ->  (
a  e.  A  <->  x  e.  A ) )
43cbvexv 1811 . . 3  |-  ( E. a  a  e.  A  <->  E. x  x  e.  A
)
5 df-rex 2329 . . . . 5  |-  ( E. x  e.  A  ph  <->  E. x ( x  e.  A  /\  ph )
)
6 19.41v 1798 . . . . 5  |-  ( E. x ( x  e.  A  /\  ph )  <->  ( E. x  x  e.  A  /\  ph )
)
75, 6bitri 177 . . . 4  |-  ( E. x  e.  A  ph  <->  ( E. x  x  e.  A  /\  ph )
)
87baibr 840 . . 3  |-  ( E. x  x  e.  A  ->  ( ph  <->  E. x  e.  A  ph ) )
94, 8sylbi 118 . 2  |-  ( E. a  a  e.  A  ->  ( ph  <->  E. x  e.  A  ph ) )
102, 9sylbir 129 1  |-  ( E. y  y  e.  A  ->  ( ph  <->  E. x  e.  A  ph ) )
Colors of variables: wff set class
Syntax hints:    -> wi 4    /\ wa 101    <-> wb 102   E.wex 1397    e. wcel 1409   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-7 1353  ax-gen 1354  ax-ie1 1398  ax-ie2 1399  ax-8 1411  ax-4 1416  ax-17 1435  ax-i9 1439  ax-ial 1443  ax-ext 2038
This theorem depends on definitions:  df-bi 114  df-cleq 2049  df-clel 2052  df-rex 2329
This theorem is referenced by:  r19.45mv  3343  iunconstm  3693  fconstfvm  5407  ltexprlemloc  6763
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