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Theorem reldisj 3498
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 3169 . . . 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 3162 . . . . . . 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 1739 . . . 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 1611 . 2  |-  ( A 
C_  C  ->  ( A. x ( x  e.  A  ->  -.  x  e.  B )  <->  A. x
( x  e.  A  ->  x  e.  ( C 
\  B ) ) ) )
9 disj1 3497 . 2  |-  ( ( A  i^i  B )  =  (/)  <->  A. x ( x  e.  A  ->  -.  x  e.  B )
)
10 dfss2 3169 . 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 1527    = wceq 1623    e. wcel 1684    \ cdif 3149    i^i cin 3151    C_ wss 3152   (/)c0 3455
This theorem is referenced by:  disj2  3502  oacomf1olem  6562  domdifsn  6945  elfiun  7183  cantnfp1lem3  7382  ssxr  8892  structcnvcnv  13159  fidomndrng  16048  elcls  16810  ist1-2  17075  nrmsep2  17084  nrmsep  17085  isnrm3  17087  isreg2  17105  hauscmplem  17133  connsub  17147  iunconlem  17153  llycmpkgen2  17245  hausdiag  17339  trfil3  17583  isufil2  17603  filufint  17615  blcld  18051  i1fima2  19034  i1fd  19036
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-6 1703  ax-7 1708  ax-11 1715  ax-12 1866  ax-ext 2264
This theorem depends on definitions:  df-bi 177  df-or 359  df-an 360  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-ral 2548  df-v 2790  df-dif 3155  df-in 3159  df-ss 3166  df-nul 3456
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