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Theorem ineq1 3419
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 2298 . . . 4  |-  ( A  =  B  ->  (
x  e.  A  <->  x  e.  B ) )
21anbi1d 465 . . 3  |-  ( A  =  B  ->  (
( x  e.  A  /\  x  e.  C
)  <->  ( x  e.  B  /\  x  e.  C ) ) )
3 elin 3406 . . 3  |-  ( x  e.  ( A  i^i  C )  <->  ( x  e.  A  /\  x  e.  C ) )
4 elin 3406 . . 3  |-  ( x  e.  ( B  i^i  C )  <->  ( x  e.  B  /\  x  e.  C ) )
52, 3, 43bitr4g 223 . 2  |-  ( A  =  B  ->  (
x  e.  ( A  i^i  C )  <->  x  e.  ( B  i^i  C ) ) )
65eqrdv 2232 1  |-  ( A  =  B  ->  ( A  i^i  C )  =  ( B  i^i  C
) )
Colors of variables: wff set class
Syntax hints:    -> wi 4    /\ wa 104    = wceq 1398    e. wcel 2205    i^i cin 3213
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-io 717  ax-5 1496  ax-7 1497  ax-gen 1498  ax-ie1 1542  ax-ie2 1543  ax-8 1553  ax-10 1554  ax-11 1555  ax-i12 1556  ax-bndl 1558  ax-4 1559  ax-17 1575  ax-i9 1579  ax-ial 1583  ax-i5r 1584  ax-ext 2216
This theorem depends on definitions:  df-bi 117  df-tru 1401  df-nf 1510  df-sb 1812  df-clab 2221  df-cleq 2227  df-clel 2230  df-nfc 2375  df-v 2817  df-in 3220
This theorem is referenced by:  ineq2  3420  ineq12  3421  ineq1i  3422  ineq1d  3425  dfrab3ss  3503  intprg  3987  inex1g  4251  reseq1  5037  fiintim  7204  uzin2  11697  ballotfilemgval  13211  ressvalsets  13361  elrestr  13544  tgval  13559  inopn  14994  isbasisg  15035  basis1  15038  basis2  15039  ntrfval  15091  tgrest  15160  restco  15165  restsn  15171  restopnb  15172  txrest  15267  metrest  15497  qtopbasss  15512  bdinex1g  16797
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