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Theorem hbex 1636
Description: If  x is not free in  ph, it is not free in  E. y ph. (Contributed by NM, 5-Aug-1993.) (Revised by NM, 2-Feb-2015.)
Hypothesis
Ref Expression
hbex.1  |-  ( ph  ->  A. x ph )
Assertion
Ref Expression
hbex  |-  ( E. y ph  ->  A. x E. y ph )

Proof of Theorem hbex
StepHypRef Expression
1 hbe1 1495 . . 3  |-  ( E. y ph  ->  A. y E. y ph )
21hbal 1477 . 2  |-  ( A. x E. y ph  ->  A. y A. x E. y ph )
3 hbex.1 . . 3  |-  ( ph  ->  A. x ph )
4 19.8a 1590 . . 3  |-  ( ph  ->  E. y ph )
53, 4alrimih 1469 . 2  |-  ( ph  ->  A. x E. y ph )
62, 5exlimih 1593 1  |-  ( E. y ph  ->  A. x E. y ph )
Colors of variables: wff set class
Syntax hints:    -> wi 4   A.wal 1351   E.wex 1492
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-5 1447  ax-7 1448  ax-gen 1449  ax-ie1 1493  ax-ie2 1494  ax-4 1510
This theorem depends on definitions:  df-bi 117
This theorem is referenced by:  nfex  1637  excomim  1663  19.12  1665  cbvexh  1755  cbvexdh  1926  hbsbv  1941  hbeu1  2036  hbmo  2065  moexexdc  2110
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