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Theorem riotaiota 6310
Description: Restricted iota in terms of iota. (Contributed by NM, 15-Sep-2011.)
Assertion
Ref Expression
riotaiota  |-  ( E! x  e.  A  ph  ->  ( iota_ x  e.  A ph )  =  ( iota x ( x  e.  A  /\  ph )
) )

Proof of Theorem riotaiota
StepHypRef Expression
1 df-riota 6304 . 2  |-  ( iota_ x  e.  A ph )  =  if ( E! x  e.  A  ph ,  ( iota x ( x  e.  A  /\  ph ) ) ,  (
Undef `  { x  |  x  e.  A }
) )
2 iftrue 3571 . 2  |-  ( E! x  e.  A  ph  ->  if ( E! x  e.  A  ph ,  ( iota x ( x  e.  A  /\  ph ) ) ,  (
Undef `  { x  |  x  e.  A }
) )  =  ( iota x ( x  e.  A  /\  ph ) ) )
31, 2syl5eq 2327 1  |-  ( E! x  e.  A  ph  ->  ( iota_ x  e.  A ph )  =  ( iota x ( x  e.  A  /\  ph )
) )
Colors of variables: wff set class
Syntax hints:    -> wi 4    /\ wa 358    = wceq 1623    e. wcel 1684   {cab 2269   E!wreu 2545   ifcif 3565   iotacio 5217   ` cfv 5255   Undefcund 6296   iota_crio 6297
This theorem is referenced by:  riotauni  6311  riotacl2  6318  riota1  6323  riota2df  6325  snriota  6335  riotaprc  6342  ismgmid  14387  q1peqb  19540  adjval  22470
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-3 7  ax-mp 8  ax-gen 1533  ax-5 1544  ax-17 1603  ax-9 1635  ax-8 1643  ax-6 1703  ax-7 1708  ax-11 1715  ax-12 1866  ax-ext 2264
This theorem depends on definitions:  df-bi 177  df-or 359  df-an 360  df-tru 1310  df-ex 1529  df-nf 1532  df-sb 1630  df-clab 2270  df-cleq 2276  df-clel 2279  df-if 3566  df-riota 6304
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