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Theorem exmo 2201
Description: Something exists or at most one exists. (Contributed by NM, 8-Mar-1995.)
Assertion
Ref Expression
exmo  |-  ( E. x ph  \/  E* x ph )

Proof of Theorem exmo
StepHypRef Expression
1 pm2.21 100 . . 3  |-  ( -. 
E. x ph  ->  ( E. x ph  ->  E! x ph ) )
2 df-mo 2161 . . 3  |-  ( E* x ph  <->  ( E. x ph  ->  E! x ph ) )
31, 2sylibr 203 . 2  |-  ( -. 
E. x ph  ->  E* x ph )
43orri 365 1  |-  ( E. x ph  \/  E* x ph )
Colors of variables: wff set class
Syntax hints:   -. wn 3    -> wi 4    \/ wo 357   E.wex 1531   E!weu 2156   E*wmo 2157
This theorem is referenced by:  moexex  2225  mo2icl  2957  mosubopt  4280  dff3  5689  brdom3  8169  mof  24921
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-3 7  ax-mp 8
This theorem depends on definitions:  df-bi 177  df-or 359  df-mo 2161
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