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Theorem nfmod 1992
Description: Bound-variable hypothesis builder for "at most one." (Contributed by Mario Carneiro, 14-Nov-2016.)
Hypotheses
Ref Expression
nfeud.1  |-  F/ y
ph
nfeud.2  |-  ( ph  ->  F/ x ps )
Assertion
Ref Expression
nfmod  |-  ( ph  ->  F/ x E* y ps )

Proof of Theorem nfmod
StepHypRef Expression
1 df-mo 1979 . 2  |-  ( E* y ps  <->  ( E. y ps  ->  E! y ps ) )
2 nfeud.1 . . . 4  |-  F/ y
ph
3 nfeud.2 . . . 4  |-  ( ph  ->  F/ x ps )
42, 3nfexd 1717 . . 3  |-  ( ph  ->  F/ x E. y ps )
52, 3nfeud 1991 . . 3  |-  ( ph  ->  F/ x E! y ps )
64, 5nfimd 1547 . 2  |-  ( ph  ->  F/ x ( E. y ps  ->  E! y ps ) )
71, 6nfxfrd 1434 1  |-  ( ph  ->  F/ x E* y ps )
Colors of variables: wff set class
Syntax hints:    -> wi 4   F/wnf 1419   E.wex 1451   E!weu 1975   E*wmo 1976
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-io 681  ax-5 1406  ax-7 1407  ax-gen 1408  ax-ie1 1452  ax-ie2 1453  ax-8 1465  ax-10 1466  ax-11 1467  ax-i12 1468  ax-bndl 1469  ax-4 1470  ax-17 1489  ax-i9 1493  ax-ial 1497  ax-i5r 1498
This theorem depends on definitions:  df-bi 116  df-tru 1317  df-nf 1420  df-sb 1719  df-eu 1978  df-mo 1979
This theorem is referenced by:  nfmo  1995
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