ILE Home Intuitionistic Logic Explorer < Previous   Next >
Nearby theorems
Mirrors  >  Home  >  ILE Home  >  Th. List  >  unssin Unicode version

Theorem unssin 3412
Description: Union as a subset of class complement and intersection (De Morgan's law). One direction of the definition of union in [Mendelson] p. 231. This would be an equality, rather than subset, in classical logic. (Contributed by Jim Kingdon, 25-Jul-2018.)
Assertion
Ref Expression
unssin  |-  ( A  u.  B )  C_  ( _V  \  (
( _V  \  A
)  i^i  ( _V  \  B ) ) )

Proof of Theorem unssin
Dummy variable  x is distinct from all other variables.
StepHypRef Expression
1 oranim 783 . . . . 5  |-  ( ( x  e.  A  \/  x  e.  B )  ->  -.  ( -.  x  e.  A  /\  -.  x  e.  B ) )
2 eldifn 3296 . . . . . 6  |-  ( x  e.  ( _V  \  A )  ->  -.  x  e.  A )
3 eldifn 3296 . . . . . 6  |-  ( x  e.  ( _V  \  B )  ->  -.  x  e.  B )
42, 3anim12i 338 . . . . 5  |-  ( ( x  e.  ( _V 
\  A )  /\  x  e.  ( _V  \  B ) )  -> 
( -.  x  e.  A  /\  -.  x  e.  B ) )
51, 4nsyl 629 . . . 4  |-  ( ( x  e.  A  \/  x  e.  B )  ->  -.  ( x  e.  ( _V  \  A
)  /\  x  e.  ( _V  \  B ) ) )
6 elin 3356 . . . 4  |-  ( x  e.  ( ( _V 
\  A )  i^i  ( _V  \  B
) )  <->  ( x  e.  ( _V  \  A
)  /\  x  e.  ( _V  \  B ) ) )
75, 6sylnibr 679 . . 3  |-  ( ( x  e.  A  \/  x  e.  B )  ->  -.  x  e.  ( ( _V  \  A
)  i^i  ( _V  \  B ) ) )
8 elun 3314 . . 3  |-  ( x  e.  ( A  u.  B )  <->  ( x  e.  A  \/  x  e.  B ) )
9 vex 2775 . . . 4  |-  x  e. 
_V
10 eldif 3175 . . . 4  |-  ( x  e.  ( _V  \ 
( ( _V  \  A )  i^i  ( _V  \  B ) ) )  <->  ( x  e. 
_V  /\  -.  x  e.  ( ( _V  \  A )  i^i  ( _V  \  B ) ) ) )
119, 10mpbiran 943 . . 3  |-  ( x  e.  ( _V  \ 
( ( _V  \  A )  i^i  ( _V  \  B ) ) )  <->  -.  x  e.  ( ( _V  \  A )  i^i  ( _V  \  B ) ) )
127, 8, 113imtr4i 201 . 2  |-  ( x  e.  ( A  u.  B )  ->  x  e.  ( _V  \  (
( _V  \  A
)  i^i  ( _V  \  B ) ) ) )
1312ssriv 3197 1  |-  ( A  u.  B )  C_  ( _V  \  (
( _V  \  A
)  i^i  ( _V  \  B ) ) )
Colors of variables: wff set class
Syntax hints:   -. wn 3    /\ wa 104    \/ wo 710    e. wcel 2176   _Vcvv 2772    \ cdif 3163    u. cun 3164    i^i cin 3165    C_ wss 3166
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-in1 615  ax-in2 616  ax-io 711  ax-5 1470  ax-7 1471  ax-gen 1472  ax-ie1 1516  ax-ie2 1517  ax-8 1527  ax-10 1528  ax-11 1529  ax-i12 1530  ax-bndl 1532  ax-4 1533  ax-17 1549  ax-i9 1553  ax-ial 1557  ax-i5r 1558  ax-ext 2187
This theorem depends on definitions:  df-bi 117  df-tru 1376  df-nf 1484  df-sb 1786  df-clab 2192  df-cleq 2198  df-clel 2201  df-nfc 2337  df-v 2774  df-dif 3168  df-un 3170  df-in 3172  df-ss 3179
This theorem is referenced by: (None)
  Copyright terms: Public domain W3C validator