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Theorem dmin 4543
Description: The domain of an intersection belong to the intersection of domains. Theorem 6 of [Suppes] p. 60. (Contributed by NM, 15-Sep-2004.)
Assertion
Ref Expression
dmin  |-  dom  ( A  i^i  B )  C_  ( dom  A  i^i  dom  B )

Proof of Theorem dmin
Dummy variables  x  y are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 19.40 1522 . . 3  |-  ( E. y ( <. x ,  y >.  e.  A  /\  <. x ,  y
>.  e.  B )  -> 
( E. y <.
x ,  y >.  e.  A  /\  E. y <. x ,  y >.  e.  B ) )
2 vex 2560 . . . . 5  |-  x  e. 
_V
32eldm2 4533 . . . 4  |-  ( x  e.  dom  ( A  i^i  B )  <->  E. y <. x ,  y >.  e.  ( A  i^i  B
) )
4 elin 3126 . . . . 5  |-  ( <.
x ,  y >.  e.  ( A  i^i  B
)  <->  ( <. x ,  y >.  e.  A  /\  <. x ,  y
>.  e.  B ) )
54exbii 1496 . . . 4  |-  ( E. y <. x ,  y
>.  e.  ( A  i^i  B )  <->  E. y ( <.
x ,  y >.  e.  A  /\  <. x ,  y >.  e.  B
) )
63, 5bitri 173 . . 3  |-  ( x  e.  dom  ( A  i^i  B )  <->  E. y
( <. x ,  y
>.  e.  A  /\  <. x ,  y >.  e.  B
) )
7 elin 3126 . . . 4  |-  ( x  e.  ( dom  A  i^i  dom  B )  <->  ( x  e.  dom  A  /\  x  e.  dom  B ) )
82eldm2 4533 . . . . 5  |-  ( x  e.  dom  A  <->  E. y <. x ,  y >.  e.  A )
92eldm2 4533 . . . . 5  |-  ( x  e.  dom  B  <->  E. y <. x ,  y >.  e.  B )
108, 9anbi12i 433 . . . 4  |-  ( ( x  e.  dom  A  /\  x  e.  dom  B )  <->  ( E. y <. x ,  y >.  e.  A  /\  E. y <. x ,  y >.  e.  B ) )
117, 10bitri 173 . . 3  |-  ( x  e.  ( dom  A  i^i  dom  B )  <->  ( E. y <. x ,  y
>.  e.  A  /\  E. y <. x ,  y
>.  e.  B ) )
121, 6, 113imtr4i 190 . 2  |-  ( x  e.  dom  ( A  i^i  B )  ->  x  e.  ( dom  A  i^i  dom  B )
)
1312ssriv 2949 1  |-  dom  ( A  i^i  B )  C_  ( dom  A  i^i  dom  B )
Colors of variables: wff set class
Syntax hints:    /\ wa 97   E.wex 1381    e. wcel 1393    i^i cin 2916    C_ wss 2917   <.cop 3378   dom cdm 4345
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 99  ax-ia2 100  ax-ia3 101  ax-io 630  ax-5 1336  ax-7 1337  ax-gen 1338  ax-ie1 1382  ax-ie2 1383  ax-8 1395  ax-10 1396  ax-11 1397  ax-i12 1398  ax-bndl 1399  ax-4 1400  ax-17 1419  ax-i9 1423  ax-ial 1427  ax-i5r 1428  ax-ext 2022
This theorem depends on definitions:  df-bi 110  df-3an 887  df-tru 1246  df-nf 1350  df-sb 1646  df-clab 2027  df-cleq 2033  df-clel 2036  df-nfc 2167  df-v 2559  df-un 2922  df-in 2924  df-ss 2931  df-sn 3381  df-pr 3382  df-op 3384  df-br 3765  df-dm 4355
This theorem is referenced by:  rnin  4733
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