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Theorem exmo 2325
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 pm2.21 102 . . 3  |-  ( -. 
E. x ph  ->  ( E. x ph  ->  E! x ph ) )
2 df-mo 2285 . . 3  |-  ( E* x ph  <->  ( E. x ph  ->  E! x ph ) )
31, 2sylibr 204 . 2  |-  ( -. 
E. x ph  ->  E* x ph )
43orri 366 1  |-  ( E. x ph  \/  E* x ph )
Colors of variables: wff set class
Syntax hints:   -. wn 3    -> wi 4    \/ wo 358   E.wex 1550   E!weu 2280   E*wmo 2281
This theorem is referenced by:  moexex  2349  mo2icl  3105  mosubopt  4446  dff3  5874  brdom3  8398  mof  26152
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 178  df-or 360  df-mo 2285
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