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Theorem reldisj 3511
Description: Two ways of saying that two classes are disjoint, using the complement of  B relative to a universe  C. (Contributed by NM, 15-Feb-2007.) (Proof shortened by Andrew Salmon, 26-Jun-2011.)
Assertion
Ref Expression
reldisj  |-  ( A 
C_  C  ->  (
( A  i^i  B
)  =  (/)  <->  A  C_  ( C  \  B ) ) )

Proof of Theorem reldisj
Dummy variable  x is distinct from all other variables.
StepHypRef Expression
1 dfss2 3182 . . . 4  |-  ( A 
C_  C  <->  A. x
( x  e.  A  ->  x  e.  C ) )
2 pm5.44 877 . . . . . 6  |-  ( ( x  e.  A  ->  x  e.  C )  ->  ( ( x  e.  A  ->  -.  x  e.  B )  <->  ( x  e.  A  ->  ( x  e.  C  /\  -.  x  e.  B )
) ) )
3 eldif 3175 . . . . . . 7  |-  ( x  e.  ( C  \  B )  <->  ( x  e.  C  /\  -.  x  e.  B ) )
43imbi2i 303 . . . . . 6  |-  ( ( x  e.  A  ->  x  e.  ( C  \  B ) )  <->  ( x  e.  A  ->  ( x  e.  C  /\  -.  x  e.  B )
) )
52, 4syl6bbr 254 . . . . 5  |-  ( ( x  e.  A  ->  x  e.  C )  ->  ( ( x  e.  A  ->  -.  x  e.  B )  <->  ( x  e.  A  ->  x  e.  ( C  \  B
) ) ) )
65sps 1751 . . . 4  |-  ( A. x ( x  e.  A  ->  x  e.  C )  ->  (
( x  e.  A  ->  -.  x  e.  B
)  <->  ( x  e.  A  ->  x  e.  ( C  \  B ) ) ) )
71, 6sylbi 187 . . 3  |-  ( A 
C_  C  ->  (
( x  e.  A  ->  -.  x  e.  B
)  <->  ( x  e.  A  ->  x  e.  ( C  \  B ) ) ) )
87albidv 1615 . 2  |-  ( A 
C_  C  ->  ( A. x ( x  e.  A  ->  -.  x  e.  B )  <->  A. x
( x  e.  A  ->  x  e.  ( C 
\  B ) ) ) )
9 disj1 3510 . 2  |-  ( ( A  i^i  B )  =  (/)  <->  A. x ( x  e.  A  ->  -.  x  e.  B )
)
10 dfss2 3182 . 2  |-  ( A 
C_  ( C  \  B )  <->  A. x
( x  e.  A  ->  x  e.  ( C 
\  B ) ) )
118, 9, 103bitr4g 279 1  |-  ( A 
C_  C  ->  (
( A  i^i  B
)  =  (/)  <->  A  C_  ( C  \  B ) ) )
Colors of variables: wff set class
Syntax hints:   -. wn 3    -> wi 4    <-> wb 176    /\ wa 358   A.wal 1530    = wceq 1632    e. wcel 1696    \ cdif 3162    i^i cin 3164    C_ wss 3165   (/)c0 3468
This theorem is referenced by:  disj2  3515  oacomf1olem  6578  domdifsn  6961  elfiun  7199  cantnfp1lem3  7398  ssxr  8908  structcnvcnv  13175  fidomndrng  16064  elcls  16826  ist1-2  17091  nrmsep2  17100  nrmsep  17101  isnrm3  17103  isreg2  17121  hauscmplem  17149  connsub  17163  iunconlem  17169  llycmpkgen2  17261  hausdiag  17355  trfil3  17599  isufil2  17619  filufint  17631  blcld  18067  i1fima2  19050  i1fd  19052  itg2addnclem2  25004
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-3 7  ax-mp 8  ax-gen 1536  ax-5 1547  ax-17 1606  ax-9 1644  ax-8 1661  ax-6 1715  ax-7 1720  ax-11 1727  ax-12 1878  ax-ext 2277
This theorem depends on definitions:  df-bi 177  df-or 359  df-an 360  df-tru 1310  df-ex 1532  df-nf 1535  df-sb 1639  df-clab 2283  df-cleq 2289  df-clel 2292  df-nfc 2421  df-ral 2561  df-v 2803  df-dif 3168  df-in 3172  df-ss 3179  df-nul 3469
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