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Theorem iunxpf 4832
Description: Indexed union on a cross product is equals a double indexed union. The hypothesis specifies an implicit substitution. (Contributed by NM, 19-Dec-2008.)
Hypotheses
Ref Expression
iunxpf.1  |-  F/_ y C
iunxpf.2  |-  F/_ z C
iunxpf.3  |-  F/_ x D
iunxpf.4  |-  ( x  =  <. y ,  z
>.  ->  C  =  D )
Assertion
Ref Expression
iunxpf  |-  U_ x  e.  ( A  X.  B
) C  =  U_ y  e.  A  U_ z  e.  B  D
Distinct variable groups:    x, y, A    x, z, B, y
Allowed substitution hints:    A( z)    C( x, y, z)    D( x, y, z)

Proof of Theorem iunxpf
Dummy variable  w is distinct from all other variables.
StepHypRef Expression
1 iunxpf.1 . . . . 5  |-  F/_ y C
21nfcri 2413 . . . 4  |-  F/ y  w  e.  C
3 iunxpf.2 . . . . 5  |-  F/_ z C
43nfcri 2413 . . . 4  |-  F/ z  w  e.  C
5 iunxpf.3 . . . . 5  |-  F/_ x D
65nfcri 2413 . . . 4  |-  F/ x  w  e.  D
7 iunxpf.4 . . . . 5  |-  ( x  =  <. y ,  z
>.  ->  C  =  D )
87eleq2d 2350 . . . 4  |-  ( x  =  <. y ,  z
>.  ->  ( w  e.  C  <->  w  e.  D
) )
92, 4, 6, 8rexxpf 4831 . . 3  |-  ( E. x  e.  ( A  X.  B ) w  e.  C  <->  E. y  e.  A  E. z  e.  B  w  e.  D )
10 eliun 3909 . . 3  |-  ( w  e.  U_ x  e.  ( A  X.  B
) C  <->  E. x  e.  ( A  X.  B
) w  e.  C
)
11 eliun 3909 . . . 4  |-  ( w  e.  U_ y  e.  A  U_ z  e.  B  D  <->  E. y  e.  A  w  e.  U_ z  e.  B  D
)
12 eliun 3909 . . . . 5  |-  ( w  e.  U_ z  e.  B  D  <->  E. z  e.  B  w  e.  D )
1312rexbii 2568 . . . 4  |-  ( E. y  e.  A  w  e.  U_ z  e.  B  D  <->  E. y  e.  A  E. z  e.  B  w  e.  D )
1411, 13bitri 240 . . 3  |-  ( w  e.  U_ y  e.  A  U_ z  e.  B  D  <->  E. y  e.  A  E. z  e.  B  w  e.  D )
159, 10, 143bitr4i 268 . 2  |-  ( w  e.  U_ x  e.  ( A  X.  B
) C  <->  w  e.  U_ y  e.  A  U_ z  e.  B  D
)
1615eqriv 2280 1  |-  U_ x  e.  ( A  X.  B
) C  =  U_ y  e.  A  U_ z  e.  B  D
Colors of variables: wff set class
Syntax hints:    -> wi 4    = wceq 1623    e. wcel 1684   F/_wnfc 2406   E.wrex 2544   <.cop 3643   U_ciun 3905    X. cxp 4687
This theorem is referenced by:  dfmpt2  6209
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-3 7  ax-mp 8  ax-gen 1533  ax-5 1544  ax-17 1603  ax-9 1635  ax-8 1643  ax-14 1688  ax-6 1703  ax-7 1708  ax-11 1715  ax-12 1866  ax-ext 2264  ax-sep 4141  ax-nul 4149  ax-pr 4214
This theorem depends on definitions:  df-bi 177  df-or 359  df-an 360  df-3an 936  df-tru 1310  df-ex 1529  df-nf 1532  df-sb 1630  df-clab 2270  df-cleq 2276  df-clel 2279  df-nfc 2408  df-ne 2448  df-ral 2548  df-rex 2549  df-rab 2552  df-v 2790  df-sbc 2992  df-csb 3082  df-dif 3155  df-un 3157  df-in 3159  df-ss 3166  df-nul 3456  df-if 3566  df-sn 3646  df-pr 3647  df-op 3649  df-iun 3907  df-opab 4078  df-xp 4695  df-rel 4696
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