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Theorem isfin6 8180
Description: Definition of a VI-finite set. (Contributed by Stefan O'Rear, 16-May-2015.)
Assertion
Ref Expression
isfin6  |-  ( A  e. FinVI  <-> 
( A  ~<  2o  \/  A  ~<  ( A  X.  A ) ) )

Proof of Theorem isfin6
Dummy variable  x is distinct from all other variables.
StepHypRef Expression
1 df-fin6 8170 . . 3  |- FinVI  =  {
x  |  ( x 
~<  2o  \/  x  ~<  ( x  X.  x ) ) }
21eleq2i 2500 . 2  |-  ( A  e. FinVI  <-> 
A  e.  { x  |  ( x  ~<  2o  \/  x  ~<  (
x  X.  x ) ) } )
3 relsdom 7116 . . . . 5  |-  Rel  ~<
43brrelexi 4918 . . . 4  |-  ( A 
~<  2o  ->  A  e.  _V )
53brrelexi 4918 . . . 4  |-  ( A 
~<  ( A  X.  A
)  ->  A  e.  _V )
64, 5jaoi 369 . . 3  |-  ( ( A  ~<  2o  \/  A  ~<  ( A  X.  A ) )  ->  A  e.  _V )
7 breq1 4215 . . . 4  |-  ( x  =  A  ->  (
x  ~<  2o  <->  A  ~<  2o ) )
8 id 20 . . . . 5  |-  ( x  =  A  ->  x  =  A )
98, 8xpeq12d 4903 . . . . 5  |-  ( x  =  A  ->  (
x  X.  x )  =  ( A  X.  A ) )
108, 9breq12d 4225 . . . 4  |-  ( x  =  A  ->  (
x  ~<  ( x  X.  x )  <->  A  ~<  ( A  X.  A ) ) )
117, 10orbi12d 691 . . 3  |-  ( x  =  A  ->  (
( x  ~<  2o  \/  x  ~<  ( x  X.  x ) )  <->  ( A  ~<  2o  \/  A  ~<  ( A  X.  A ) ) ) )
126, 11elab3 3089 . 2  |-  ( A  e.  { x  |  ( x  ~<  2o  \/  x  ~<  ( x  X.  x ) ) }  <-> 
( A  ~<  2o  \/  A  ~<  ( A  X.  A ) ) )
132, 12bitri 241 1  |-  ( A  e. FinVI  <-> 
( A  ~<  2o  \/  A  ~<  ( A  X.  A ) ) )
Colors of variables: wff set class
Syntax hints:    <-> wb 177    \/ wo 358    = wceq 1652    e. wcel 1725   {cab 2422   _Vcvv 2956   class class class wbr 4212    X. cxp 4876   2oc2o 6718    ~< csdm 7108  FinVIcfin6 8163
This theorem is referenced by:  fin56  8273  fin67  8275
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-3 7  ax-mp 8  ax-gen 1555  ax-5 1566  ax-17 1626  ax-9 1666  ax-8 1687  ax-14 1729  ax-6 1744  ax-7 1749  ax-11 1761  ax-12 1950  ax-ext 2417  ax-sep 4330  ax-nul 4338  ax-pr 4403
This theorem depends on definitions:  df-bi 178  df-or 360  df-an 361  df-3an 938  df-tru 1328  df-ex 1551  df-nf 1554  df-sb 1659  df-clab 2423  df-cleq 2429  df-clel 2432  df-nfc 2561  df-ne 2601  df-ral 2710  df-rex 2711  df-rab 2714  df-v 2958  df-dif 3323  df-un 3325  df-in 3327  df-ss 3334  df-nul 3629  df-if 3740  df-sn 3820  df-pr 3821  df-op 3823  df-br 4213  df-opab 4267  df-xp 4884  df-rel 4885  df-dom 7111  df-sdom 7112  df-fin6 8170
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