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Theorem exmonim 1999
Description: There is at most one of something which does not exist. Unlike exmodc 1998 there is no decidability condition. (Contributed by Jim Kingdon, 22-Sep-2018.)
Assertion
Ref Expression
exmonim  |-  ( -. 
E. x ph  ->  E* x ph )

Proof of Theorem exmonim
StepHypRef Expression
1 pm2.21 582 . 2  |-  ( -. 
E. x ph  ->  ( E. x ph  ->  E! x ph ) )
2 df-mo 1952 . 2  |-  ( E* x ph  <->  ( E. x ph  ->  E! x ph ) )
31, 2sylibr 132 1  |-  ( -. 
E. x ph  ->  E* x ph )
Colors of variables: wff set class
Syntax hints:   -. wn 3    -> wi 4   E.wex 1426   E!weu 1948   E*wmo 1949
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 104  ax-ia2 105  ax-ia3 106  ax-in2 580
This theorem depends on definitions:  df-bi 115  df-mo 1952
This theorem is referenced by: (None)
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