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Theorem eliotaeu 5187
Description: An inhabited iota expression has a unique value. (Contributed by Jim Kingdon, 22-Nov-2024.)
Assertion
Ref Expression
eliotaeu  |-  ( A  e.  ( iota x ph )  ->  E! x ph )

Proof of Theorem eliotaeu
Dummy variable  y is distinct from all other variables.
StepHypRef Expression
1 exsimpr 1611 . 2  |-  ( E. y ( A  e.  y  /\  A. x
( ph  <->  x  =  y
) )  ->  E. y A. x ( ph  <->  x  =  y ) )
2 eliota 5186 . 2  |-  ( A  e.  ( iota x ph )  <->  E. y ( A  e.  y  /\  A. x ( ph  <->  x  =  y ) ) )
3 df-eu 2022 . 2  |-  ( E! x ph  <->  E. y A. x ( ph  <->  x  =  y ) )
41, 2, 33imtr4i 200 1  |-  ( A  e.  ( iota x ph )  ->  E! x ph )
Colors of variables: wff set class
Syntax hints:    -> wi 4    /\ wa 103    <-> wb 104   A.wal 1346   E.wex 1485   E!weu 2019    e. wcel 2141   iotacio 5158
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 704  ax-5 1440  ax-7 1441  ax-gen 1442  ax-ie1 1486  ax-ie2 1487  ax-8 1497  ax-10 1498  ax-11 1499  ax-i12 1500  ax-bndl 1502  ax-4 1503  ax-17 1519  ax-i9 1523  ax-ial 1527  ax-i5r 1528  ax-ext 2152
This theorem depends on definitions:  df-bi 116  df-tru 1351  df-nf 1454  df-sb 1756  df-eu 2022  df-clab 2157  df-cleq 2163  df-clel 2166  df-nfc 2301  df-rex 2454  df-v 2732  df-sn 3589  df-uni 3797  df-iota 5160
This theorem is referenced by:  iotam  5190
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