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Theorem 19.9 1532
Description: A wff may be existentially quantified with a variable not free in it. Theorem 19.9 of [Margaris] p. 89. (Contributed by FL, 24-Mar-2007.) (Revised by Mario Carneiro, 24-Sep-2016.) (Proof shortened by Wolf Lammen, 30-Dec-2017.)
Hypothesis
Ref Expression
19.9.1  F/
Assertion
Ref Expression
19.9

Proof of Theorem 19.9
StepHypRef Expression
1 19.9.1 . . 3  F/
21nfri 1409 . 2
3219.9h 1531 1
Colors of variables: wff set class
Syntax hints:   wb 98   F/wnf 1346  wex 1378
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 99  ax-ia2 100  ax-ia3 101  ax-gen 1335  ax-ie1 1379  ax-ie2 1380  ax-4 1397
This theorem depends on definitions:  df-bi 110  df-nf 1347
This theorem is referenced by:  alexim  1533  19.19  1553  19.36-1  1560  19.44  1569  19.45  1570  19.41  1573
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