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Theorem fniniseg 5599
Description: Membership in the preimage of a singleton, under a function. (Contributed by Mario Carneiro, 12-May-2014.) (Proof shortened by Mario Carneiro, 28-Apr-2015.)
Assertion
Ref Expression
fniniseg  |-  ( F  Fn  A  ->  ( C  e.  ( `' F " { B }
)  <->  ( C  e.  A  /\  ( F `
 C )  =  B ) ) )

Proof of Theorem fniniseg
StepHypRef Expression
1 elpreima 5598 . 2  |-  ( F  Fn  A  ->  ( C  e.  ( `' F " { B }
)  <->  ( C  e.  A  /\  ( F `
 C )  e. 
{ B } ) ) )
2 funfvex 5497 . . . . 5  |-  ( ( Fun  F  /\  C  e.  dom  F )  -> 
( F `  C
)  e.  _V )
3 elsng 3585 . . . . 5  |-  ( ( F `  C )  e.  _V  ->  (
( F `  C
)  e.  { B } 
<->  ( F `  C
)  =  B ) )
42, 3syl 14 . . . 4  |-  ( ( Fun  F  /\  C  e.  dom  F )  -> 
( ( F `  C )  e.  { B }  <->  ( F `  C )  =  B ) )
54funfni 5282 . . 3  |-  ( ( F  Fn  A  /\  C  e.  A )  ->  ( ( F `  C )  e.  { B }  <->  ( F `  C )  =  B ) )
65pm5.32da 448 . 2  |-  ( F  Fn  A  ->  (
( C  e.  A  /\  ( F `  C
)  e.  { B } )  <->  ( C  e.  A  /\  ( F `  C )  =  B ) ) )
71, 6bitrd 187 1  |-  ( F  Fn  A  ->  ( C  e.  ( `' F " { B }
)  <->  ( C  e.  A  /\  ( F `
 C )  =  B ) ) )
Colors of variables: wff set class
Syntax hints:    -> wi 4    /\ wa 103    <-> wb 104    = wceq 1342    e. wcel 2135   _Vcvv 2721   {csn 3570   `'ccnv 4597   dom cdm 4598   "cima 4601   Fun wfun 5176    Fn wfn 5177   ` cfv 5182
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 699  ax-5 1434  ax-7 1435  ax-gen 1436  ax-ie1 1480  ax-ie2 1481  ax-8 1491  ax-10 1492  ax-11 1493  ax-i12 1494  ax-bndl 1496  ax-4 1497  ax-17 1513  ax-i9 1517  ax-ial 1521  ax-i5r 1522  ax-14 2138  ax-ext 2146  ax-sep 4094  ax-pow 4147  ax-pr 4181
This theorem depends on definitions:  df-bi 116  df-3an 969  df-tru 1345  df-nf 1448  df-sb 1750  df-eu 2016  df-mo 2017  df-clab 2151  df-cleq 2157  df-clel 2160  df-nfc 2295  df-ral 2447  df-rex 2448  df-v 2723  df-sbc 2947  df-un 3115  df-in 3117  df-ss 3124  df-pw 3555  df-sn 3576  df-pr 3577  df-op 3579  df-uni 3784  df-br 3977  df-opab 4038  df-id 4265  df-xp 4604  df-rel 4605  df-cnv 4606  df-co 4607  df-dm 4608  df-rn 4609  df-res 4610  df-ima 4611  df-iota 5147  df-fun 5184  df-fn 5185  df-fv 5190
This theorem is referenced by:  pilem1  13241  taupi  13783
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