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Theorem iinuni 4064
Description: A relationship involving union and indexed intersection. Exercise 23 of [Enderton] p. 33. (Contributed by NM, 25-Nov-2003.) (Proof shortened by Mario Carneiro, 17-Nov-2016.)
Assertion
Ref Expression
iinuni  |-  ( A  u.  |^| B )  = 
|^|_ x  e.  B  ( A  u.  x
)
Distinct variable groups:    x, A    x, B

Proof of Theorem iinuni
Dummy variable  y is distinct from all other variables.
StepHypRef Expression
1 r19.32v 2762 . . . 4  |-  ( A. x  e.  B  (
y  e.  A  \/  y  e.  x )  <->  ( y  e.  A  \/  A. x  e.  B  y  e.  x ) )
2 elun 3392 . . . . 5  |-  ( y  e.  ( A  u.  x )  <->  ( y  e.  A  \/  y  e.  x ) )
32ralbii 2643 . . . 4  |-  ( A. x  e.  B  y  e.  ( A  u.  x
)  <->  A. x  e.  B  ( y  e.  A  \/  y  e.  x
) )
4 vex 2867 . . . . . 6  |-  y  e. 
_V
54elint2 3948 . . . . 5  |-  ( y  e.  |^| B  <->  A. x  e.  B  y  e.  x )
65orbi2i 505 . . . 4  |-  ( ( y  e.  A  \/  y  e.  |^| B )  <-> 
( y  e.  A  \/  A. x  e.  B  y  e.  x )
)
71, 3, 63bitr4ri 269 . . 3  |-  ( ( y  e.  A  \/  y  e.  |^| B )  <->  A. x  e.  B  y  e.  ( A  u.  x ) )
87abbii 2470 . 2  |-  { y  |  ( y  e.  A  \/  y  e. 
|^| B ) }  =  { y  | 
A. x  e.  B  y  e.  ( A  u.  x ) }
9 df-un 3233 . 2  |-  ( A  u.  |^| B )  =  { y  |  ( y  e.  A  \/  y  e.  |^| B ) }
10 df-iin 3987 . 2  |-  |^|_ x  e.  B  ( A  u.  x )  =  {
y  |  A. x  e.  B  y  e.  ( A  u.  x
) }
118, 9, 103eqtr4i 2388 1  |-  ( A  u.  |^| B )  = 
|^|_ x  e.  B  ( A  u.  x
)
Colors of variables: wff set class
Syntax hints:    \/ wo 357    = wceq 1642    e. wcel 1710   {cab 2344   A.wral 2619    u. cun 3226   |^|cint 3941   |^|_ciin 3985
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-3 7  ax-mp 8  ax-gen 1546  ax-5 1557  ax-17 1616  ax-9 1654  ax-8 1675  ax-6 1729  ax-7 1734  ax-11 1746  ax-12 1930  ax-ext 2339
This theorem depends on definitions:  df-bi 177  df-or 359  df-an 360  df-tru 1319  df-ex 1542  df-nf 1545  df-sb 1649  df-clab 2345  df-cleq 2351  df-clel 2354  df-nfc 2483  df-ral 2624  df-v 2866  df-un 3233  df-int 3942  df-iin 3987
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