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Theorem erdisj 6675
Description: Equivalence classes do not overlap. In other words, two equivalence classes are either equal or disjoint. Theorem 74 of [Suppes] p. 83. (Contributed by NM, 15-Jun-2004.) (Revised by Mario Carneiro, 9-Jul-2014.)
Assertion
Ref Expression
erdisj  |-  ( R  Er  X  ->  ( [ A ] R  =  [ B ] R  \/  ( [ A ] R  i^i  [ B ] R )  =  (/) ) )

Proof of Theorem erdisj
StepHypRef Expression
1 neq0 3440 . . . 4  |-  ( -.  ( [ A ] R  i^i  [ B ] R )  =  (/)  <->  E. x  x  e.  ( [ A ] R  i^i  [ B ] R ) )
2 simpl 445 . . . . . . 7  |-  ( ( R  Er  X  /\  x  e.  ( [ A ] R  i^i  [ B ] R ) )  ->  R  Er  X
)
3 elin 3333 . . . . . . . . . . 11  |-  ( x  e.  ( [ A ] R  i^i  [ B ] R )  <->  ( x  e.  [ A ] R  /\  x  e.  [ B ] R ) )
43simplbi 448 . . . . . . . . . 10  |-  ( x  e.  ( [ A ] R  i^i  [ B ] R )  ->  x  e.  [ A ] R
)
54adantl 454 . . . . . . . . 9  |-  ( ( R  Er  X  /\  x  e.  ( [ A ] R  i^i  [ B ] R ) )  ->  x  e.  [ A ] R )
6 vex 2766 . . . . . . . . . 10  |-  x  e. 
_V
7 ecexr 6633 . . . . . . . . . . 11  |-  ( x  e.  [ A ] R  ->  A  e.  _V )
85, 7syl 17 . . . . . . . . . 10  |-  ( ( R  Er  X  /\  x  e.  ( [ A ] R  i^i  [ B ] R ) )  ->  A  e.  _V )
9 elecg 6666 . . . . . . . . . 10  |-  ( ( x  e.  _V  /\  A  e.  _V )  ->  ( x  e.  [ A ] R  <->  A R x ) )
106, 8, 9sylancr 647 . . . . . . . . 9  |-  ( ( R  Er  X  /\  x  e.  ( [ A ] R  i^i  [ B ] R ) )  ->  ( x  e. 
[ A ] R  <->  A R x ) )
115, 10mpbid 203 . . . . . . . 8  |-  ( ( R  Er  X  /\  x  e.  ( [ A ] R  i^i  [ B ] R ) )  ->  A R x )
123simprbi 452 . . . . . . . . . 10  |-  ( x  e.  ( [ A ] R  i^i  [ B ] R )  ->  x  e.  [ B ] R
)
1312adantl 454 . . . . . . . . 9  |-  ( ( R  Er  X  /\  x  e.  ( [ A ] R  i^i  [ B ] R ) )  ->  x  e.  [ B ] R )
14 ecexr 6633 . . . . . . . . . . 11  |-  ( x  e.  [ B ] R  ->  B  e.  _V )
1513, 14syl 17 . . . . . . . . . 10  |-  ( ( R  Er  X  /\  x  e.  ( [ A ] R  i^i  [ B ] R ) )  ->  B  e.  _V )
16 elecg 6666 . . . . . . . . . 10  |-  ( ( x  e.  _V  /\  B  e.  _V )  ->  ( x  e.  [ B ] R  <->  B R x ) )
176, 15, 16sylancr 647 . . . . . . . . 9  |-  ( ( R  Er  X  /\  x  e.  ( [ A ] R  i^i  [ B ] R ) )  ->  ( x  e. 
[ B ] R  <->  B R x ) )
1813, 17mpbid 203 . . . . . . . 8  |-  ( ( R  Er  X  /\  x  e.  ( [ A ] R  i^i  [ B ] R ) )  ->  B R x )
192, 11, 18ertr4d 6647 . . . . . . 7  |-  ( ( R  Er  X  /\  x  e.  ( [ A ] R  i^i  [ B ] R ) )  ->  A R B )
202, 19erthi 6674 . . . . . 6  |-  ( ( R  Er  X  /\  x  e.  ( [ A ] R  i^i  [ B ] R ) )  ->  [ A ] R  =  [ B ] R )
2120ex 425 . . . . 5  |-  ( R  Er  X  ->  (
x  e.  ( [ A ] R  i^i  [ B ] R )  ->  [ A ] R  =  [ B ] R ) )
2221exlimdv 1933 . . . 4  |-  ( R  Er  X  ->  ( E. x  x  e.  ( [ A ] R  i^i  [ B ] R
)  ->  [ A ] R  =  [ B ] R ) )
231, 22syl5bi 210 . . 3  |-  ( R  Er  X  ->  ( -.  ( [ A ] R  i^i  [ B ] R )  =  (/)  ->  [ A ] R  =  [ B ] R
) )
2423orrd 369 . 2  |-  ( R  Er  X  ->  (
( [ A ] R  i^i  [ B ] R )  =  (/)  \/ 
[ A ] R  =  [ B ] R
) )
2524orcomd 379 1  |-  ( R  Er  X  ->  ( [ A ] R  =  [ B ] R  \/  ( [ A ] R  i^i  [ B ] R )  =  (/) ) )
Colors of variables: wff set class
Syntax hints:   -. wn 5    -> wi 6    <-> wb 178    \/ wo 359    /\ wa 360   E.wex 1537    = wceq 1619    e. wcel 1621   _Vcvv 2763    i^i cin 3126   (/)c0 3430   class class class wbr 3997    Er wer 6625   [cec 6626
This theorem is referenced by:  qsdisj  6704
This theorem was proved from axioms:  ax-1 7  ax-2 8  ax-3 9  ax-mp 10  ax-5 1533  ax-6 1534  ax-7 1535  ax-gen 1536  ax-8 1623  ax-11 1624  ax-14 1626  ax-17 1628  ax-12o 1664  ax-10 1678  ax-9 1684  ax-4 1692  ax-16 1927  ax-ext 2239  ax-sep 4115  ax-nul 4123  ax-pr 4186
This theorem depends on definitions:  df-bi 179  df-or 361  df-an 362  df-3an 941  df-tru 1315  df-ex 1538  df-nf 1540  df-sb 1884  df-eu 2122  df-mo 2123  df-clab 2245  df-cleq 2251  df-clel 2254  df-nfc 2383  df-ne 2423  df-ral 2523  df-rex 2524  df-rab 2527  df-v 2765  df-sbc 2967  df-dif 3130  df-un 3132  df-in 3134  df-ss 3141  df-nul 3431  df-if 3540  df-sn 3620  df-pr 3621  df-op 3623  df-br 3998  df-opab 4052  df-xp 4675  df-rel 4676  df-cnv 4677  df-co 4678  df-dm 4679  df-rn 4680  df-res 4681  df-ima 4682  df-er 6628  df-ec 6630
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