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Theorem eu4 2039
Description: Uniqueness using implicit substitution. (Contributed by NM, 26-Jul-1995.)
Hypothesis
Ref Expression
eu4.1  |-  ( x  =  y  ->  ( ph 
<->  ps ) )
Assertion
Ref Expression
eu4  |-  ( E! x ph  <->  ( E. x ph  /\  A. x A. y ( ( ph  /\ 
ps )  ->  x  =  y ) ) )
Distinct variable groups:    x, y    ph, y    ps, x
Allowed substitution hints:    ph( x)    ps( y)

Proof of Theorem eu4
StepHypRef Expression
1 eu5 2024 . 2  |-  ( E! x ph  <->  ( E. x ph  /\  E* x ph ) )
2 eu4.1 . . . 4  |-  ( x  =  y  ->  ( ph 
<->  ps ) )
32mo4 2038 . . 3  |-  ( E* x ph  <->  A. x A. y ( ( ph  /\ 
ps )  ->  x  =  y ) )
43anbi2i 452 . 2  |-  ( ( E. x ph  /\  E* x ph )  <->  ( E. x ph  /\  A. x A. y ( ( ph  /\ 
ps )  ->  x  =  y ) ) )
51, 4bitri 183 1  |-  ( E! x ph  <->  ( E. x ph  /\  A. x A. y ( ( ph  /\ 
ps )  ->  x  =  y ) ) )
Colors of variables: wff set class
Syntax hints:    -> wi 4    /\ wa 103    <-> wb 104   A.wal 1314   E.wex 1453   E!weu 1977   E*wmo 1978
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-io 683  ax-5 1408  ax-7 1409  ax-gen 1410  ax-ie1 1454  ax-ie2 1455  ax-8 1467  ax-10 1468  ax-11 1469  ax-i12 1470  ax-bndl 1471  ax-4 1472  ax-17 1491  ax-i9 1495  ax-ial 1499  ax-i5r 1500
This theorem depends on definitions:  df-bi 116  df-nf 1422  df-sb 1721  df-eu 1980  df-mo 1981
This theorem is referenced by:  euequ1  2072  eueq  2828  euind  2844  eusv1  4343  eroveu  6488  climeu  11033
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