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Theorem dfaimafn2 28028
Description: Alternate definition of the image of a function as an indexed union of singletons of function values, analogous to dfimafn2 5572. (Contributed by Alexander van der Vekens, 25-May-2017.)
Assertion
Ref Expression
dfaimafn2  |-  ( ( Fun  F  /\  A  C_ 
dom  F )  -> 
( F " A
)  =  U_ x  e.  A  { ( F''' x ) } )
Distinct variable groups:    x, A    x, F

Proof of Theorem dfaimafn2
Dummy variable  y is distinct from all other variables.
StepHypRef Expression
1 dfaimafn 28027 . . 3  |-  ( ( Fun  F  /\  A  C_ 
dom  F )  -> 
( F " A
)  =  { y  |  E. x  e.  A  ( F''' x )  =  y } )
2 iunab 3948 . . 3  |-  U_ x  e.  A  { y  |  ( F''' x )  =  y }  =  { y  |  E. x  e.  A  ( F''' x )  =  y }
31, 2syl6eqr 2333 . 2  |-  ( ( Fun  F  /\  A  C_ 
dom  F )  -> 
( F " A
)  =  U_ x  e.  A  { y  |  ( F''' x )  =  y } )
4 df-sn 3646 . . . . 5  |-  { ( F''' x ) }  =  { y  |  y  =  ( F''' x ) }
5 eqcom 2285 . . . . . 6  |-  ( y  =  ( F''' x )  <-> 
( F''' x )  =  y )
65abbii 2395 . . . . 5  |-  { y  |  y  =  ( F''' x ) }  =  { y  |  ( F''' x )  =  y }
74, 6eqtri 2303 . . . 4  |-  { ( F''' x ) }  =  { y  |  ( F''' x )  =  y }
87a1i 10 . . 3  |-  ( x  e.  A  ->  { ( F''' x ) }  =  { y  |  ( F''' x )  =  y } )
98iuneq2i 3923 . 2  |-  U_ x  e.  A  { ( F''' x ) }  =  U_ x  e.  A  {
y  |  ( F''' x )  =  y }
103, 9syl6eqr 2333 1  |-  ( ( Fun  F  /\  A  C_ 
dom  F )  -> 
( F " A
)  =  U_ x  e.  A  { ( F''' x ) } )
Colors of variables: wff set class
Syntax hints:    -> wi 4    /\ wa 358    = wceq 1623    e. wcel 1684   {cab 2269   E.wrex 2544    C_ wss 3152   {csn 3640   U_ciun 3905   dom cdm 4689   "cima 4692   Fun wfun 5249  '''cafv 27972
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-13 1686  ax-14 1688  ax-6 1703  ax-7 1708  ax-11 1715  ax-12 1866  ax-ext 2264  ax-sep 4141  ax-nul 4149  ax-pow 4188  ax-pr 4214
This theorem depends on definitions:  df-bi 177  df-or 359  df-an 360  df-3an 936  df-tru 1310  df-ex 1529  df-nf 1532  df-sb 1630  df-eu 2147  df-mo 2148  df-clab 2270  df-cleq 2276  df-clel 2279  df-nfc 2408  df-ne 2448  df-ral 2548  df-rex 2549  df-rab 2552  df-v 2790  df-sbc 2992  df-dif 3155  df-un 3157  df-in 3159  df-ss 3166  df-nul 3456  df-if 3566  df-sn 3646  df-pr 3647  df-op 3649  df-uni 3828  df-iun 3907  df-br 4024  df-opab 4078  df-id 4309  df-xp 4695  df-rel 4696  df-cnv 4697  df-co 4698  df-dm 4699  df-rn 4700  df-res 4701  df-ima 4702  df-iota 5219  df-fun 5257  df-fn 5258  df-fv 5263  df-dfat 27974  df-afv 27975
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