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Theorem ineq1 3192
Description: Equality theorem for intersection of two classes. (Contributed by NM, 14-Dec-1993.)
Assertion
Ref Expression
ineq1  |-  ( A  =  B  ->  ( A  i^i  C )  =  ( B  i^i  C
) )

Proof of Theorem ineq1
Dummy variable  x is distinct from all other variables.
StepHypRef Expression
1 eleq2 2151 . . . 4  |-  ( A  =  B  ->  (
x  e.  A  <->  x  e.  B ) )
21anbi1d 453 . . 3  |-  ( A  =  B  ->  (
( x  e.  A  /\  x  e.  C
)  <->  ( x  e.  B  /\  x  e.  C ) ) )
3 elin 3181 . . 3  |-  ( x  e.  ( A  i^i  C )  <->  ( x  e.  A  /\  x  e.  C ) )
4 elin 3181 . . 3  |-  ( x  e.  ( B  i^i  C )  <->  ( x  e.  B  /\  x  e.  C ) )
52, 3, 43bitr4g 221 . 2  |-  ( A  =  B  ->  (
x  e.  ( A  i^i  C )  <->  x  e.  ( B  i^i  C ) ) )
65eqrdv 2086 1  |-  ( A  =  B  ->  ( A  i^i  C )  =  ( B  i^i  C
) )
Colors of variables: wff set class
Syntax hints:    -> wi 4    /\ wa 102    = wceq 1289    e. wcel 1438    i^i cin 2996
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 104  ax-ia2 105  ax-ia3 106  ax-io 665  ax-5 1381  ax-7 1382  ax-gen 1383  ax-ie1 1427  ax-ie2 1428  ax-8 1440  ax-10 1441  ax-11 1442  ax-i12 1443  ax-bndl 1444  ax-4 1445  ax-17 1464  ax-i9 1468  ax-ial 1472  ax-i5r 1473  ax-ext 2070
This theorem depends on definitions:  df-bi 115  df-tru 1292  df-nf 1395  df-sb 1693  df-clab 2075  df-cleq 2081  df-clel 2084  df-nfc 2217  df-v 2621  df-in 3003
This theorem is referenced by:  ineq2  3193  ineq12  3194  ineq1i  3195  ineq1d  3198  dfrab3ss  3275  intprg  3716  inex1g  3967  reseq1  4695  uzin2  10385  bdinex1g  11449
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