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Theorem disjpr2 3434
Description: The intersection of distinct unordered pairs is disjoint. (Contributed by Alexander van der Vekens, 11-Nov-2017.)
Assertion
Ref Expression
disjpr2  |-  ( ( ( A  =/=  C  /\  B  =/=  C
)  /\  ( A  =/=  D  /\  B  =/= 
D ) )  -> 
( { A ,  B }  i^i  { C ,  D } )  =  (/) )

Proof of Theorem disjpr2
StepHypRef Expression
1 df-pr 3382 . . . 4  |-  { C ,  D }  =  ( { C }  u.  { D } )
21a1i 9 . . 3  |-  ( ( ( A  =/=  C  /\  B  =/=  C
)  /\  ( A  =/=  D  /\  B  =/= 
D ) )  ->  { C ,  D }  =  ( { C }  u.  { D } ) )
32ineq2d 3138 . 2  |-  ( ( ( A  =/=  C  /\  B  =/=  C
)  /\  ( A  =/=  D  /\  B  =/= 
D ) )  -> 
( { A ,  B }  i^i  { C ,  D } )  =  ( { A ,  B }  i^i  ( { C }  u.  { D } ) ) )
4 indi 3184 . . 3  |-  ( { A ,  B }  i^i  ( { C }  u.  { D } ) )  =  ( ( { A ,  B }  i^i  { C }
)  u.  ( { A ,  B }  i^i  { D } ) )
5 df-pr 3382 . . . . . . . 8  |-  { A ,  B }  =  ( { A }  u.  { B } )
65ineq1i 3134 . . . . . . 7  |-  ( { A ,  B }  i^i  { C } )  =  ( ( { A }  u.  { B } )  i^i  { C } )
7 indir 3186 . . . . . . 7  |-  ( ( { A }  u.  { B } )  i^i 
{ C } )  =  ( ( { A }  i^i  { C } )  u.  ( { B }  i^i  { C } ) )
86, 7eqtri 2060 . . . . . 6  |-  ( { A ,  B }  i^i  { C } )  =  ( ( { A }  i^i  { C } )  u.  ( { B }  i^i  { C } ) )
9 disjsn2 3433 . . . . . . . . . 10  |-  ( A  =/=  C  ->  ( { A }  i^i  { C } )  =  (/) )
109adantr 261 . . . . . . . . 9  |-  ( ( A  =/=  C  /\  B  =/=  C )  -> 
( { A }  i^i  { C } )  =  (/) )
1110adantr 261 . . . . . . . 8  |-  ( ( ( A  =/=  C  /\  B  =/=  C
)  /\  ( A  =/=  D  /\  B  =/= 
D ) )  -> 
( { A }  i^i  { C } )  =  (/) )
12 disjsn2 3433 . . . . . . . . . 10  |-  ( B  =/=  C  ->  ( { B }  i^i  { C } )  =  (/) )
1312adantl 262 . . . . . . . . 9  |-  ( ( A  =/=  C  /\  B  =/=  C )  -> 
( { B }  i^i  { C } )  =  (/) )
1413adantr 261 . . . . . . . 8  |-  ( ( ( A  =/=  C  /\  B  =/=  C
)  /\  ( A  =/=  D  /\  B  =/= 
D ) )  -> 
( { B }  i^i  { C } )  =  (/) )
1511, 14jca 290 . . . . . . 7  |-  ( ( ( A  =/=  C  /\  B  =/=  C
)  /\  ( A  =/=  D  /\  B  =/= 
D ) )  -> 
( ( { A }  i^i  { C }
)  =  (/)  /\  ( { B }  i^i  { C } )  =  (/) ) )
16 un00 3263 . . . . . . 7  |-  ( ( ( { A }  i^i  { C } )  =  (/)  /\  ( { B }  i^i  { C } )  =  (/) ) 
<->  ( ( { A }  i^i  { C }
)  u.  ( { B }  i^i  { C } ) )  =  (/) )
1715, 16sylib 127 . . . . . 6  |-  ( ( ( A  =/=  C  /\  B  =/=  C
)  /\  ( A  =/=  D  /\  B  =/= 
D ) )  -> 
( ( { A }  i^i  { C }
)  u.  ( { B }  i^i  { C } ) )  =  (/) )
188, 17syl5eq 2084 . . . . 5  |-  ( ( ( A  =/=  C  /\  B  =/=  C
)  /\  ( A  =/=  D  /\  B  =/= 
D ) )  -> 
( { A ,  B }  i^i  { C } )  =  (/) )
195ineq1i 3134 . . . . . . 7  |-  ( { A ,  B }  i^i  { D } )  =  ( ( { A }  u.  { B } )  i^i  { D } )
20 indir 3186 . . . . . . 7  |-  ( ( { A }  u.  { B } )  i^i 
{ D } )  =  ( ( { A }  i^i  { D } )  u.  ( { B }  i^i  { D } ) )
2119, 20eqtri 2060 . . . . . 6  |-  ( { A ,  B }  i^i  { D } )  =  ( ( { A }  i^i  { D } )  u.  ( { B }  i^i  { D } ) )
22 disjsn2 3433 . . . . . . . . . 10  |-  ( A  =/=  D  ->  ( { A }  i^i  { D } )  =  (/) )
2322adantr 261 . . . . . . . . 9  |-  ( ( A  =/=  D  /\  B  =/=  D )  -> 
( { A }  i^i  { D } )  =  (/) )
2423adantl 262 . . . . . . . 8  |-  ( ( ( A  =/=  C  /\  B  =/=  C
)  /\  ( A  =/=  D  /\  B  =/= 
D ) )  -> 
( { A }  i^i  { D } )  =  (/) )
25 disjsn2 3433 . . . . . . . . . 10  |-  ( B  =/=  D  ->  ( { B }  i^i  { D } )  =  (/) )
2625adantl 262 . . . . . . . . 9  |-  ( ( A  =/=  D  /\  B  =/=  D )  -> 
( { B }  i^i  { D } )  =  (/) )
2726adantl 262 . . . . . . . 8  |-  ( ( ( A  =/=  C  /\  B  =/=  C
)  /\  ( A  =/=  D  /\  B  =/= 
D ) )  -> 
( { B }  i^i  { D } )  =  (/) )
2824, 27jca 290 . . . . . . 7  |-  ( ( ( A  =/=  C  /\  B  =/=  C
)  /\  ( A  =/=  D  /\  B  =/= 
D ) )  -> 
( ( { A }  i^i  { D }
)  =  (/)  /\  ( { B }  i^i  { D } )  =  (/) ) )
29 un00 3263 . . . . . . 7  |-  ( ( ( { A }  i^i  { D } )  =  (/)  /\  ( { B }  i^i  { D } )  =  (/) ) 
<->  ( ( { A }  i^i  { D }
)  u.  ( { B }  i^i  { D } ) )  =  (/) )
3028, 29sylib 127 . . . . . 6  |-  ( ( ( A  =/=  C  /\  B  =/=  C
)  /\  ( A  =/=  D  /\  B  =/= 
D ) )  -> 
( ( { A }  i^i  { D }
)  u.  ( { B }  i^i  { D } ) )  =  (/) )
3121, 30syl5eq 2084 . . . . 5  |-  ( ( ( A  =/=  C  /\  B  =/=  C
)  /\  ( A  =/=  D  /\  B  =/= 
D ) )  -> 
( { A ,  B }  i^i  { D } )  =  (/) )
3218, 31uneq12d 3098 . . . 4  |-  ( ( ( A  =/=  C  /\  B  =/=  C
)  /\  ( A  =/=  D  /\  B  =/= 
D ) )  -> 
( ( { A ,  B }  i^i  { C } )  u.  ( { A ,  B }  i^i  { D } ) )  =  ( (/)  u.  (/) ) )
33 un0 3251 . . . 4  |-  ( (/)  u.  (/) )  =  (/)
3432, 33syl6eq 2088 . . 3  |-  ( ( ( A  =/=  C  /\  B  =/=  C
)  /\  ( A  =/=  D  /\  B  =/= 
D ) )  -> 
( ( { A ,  B }  i^i  { C } )  u.  ( { A ,  B }  i^i  { D } ) )  =  (/) )
354, 34syl5eq 2084 . 2  |-  ( ( ( A  =/=  C  /\  B  =/=  C
)  /\  ( A  =/=  D  /\  B  =/= 
D ) )  -> 
( { A ,  B }  i^i  ( { C }  u.  { D } ) )  =  (/) )
363, 35eqtrd 2072 1  |-  ( ( ( A  =/=  C  /\  B  =/=  C
)  /\  ( A  =/=  D  /\  B  =/= 
D ) )  -> 
( { A ,  B }  i^i  { C ,  D } )  =  (/) )
Colors of variables: wff set class
Syntax hints:    -> wi 4    /\ wa 97    = wceq 1243    =/= wne 2204    u. cun 2915    i^i cin 2916   (/)c0 3224   {csn 3375   {cpr 3376
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 99  ax-ia2 100  ax-ia3 101  ax-in1 544  ax-in2 545  ax-io 630  ax-5 1336  ax-7 1337  ax-gen 1338  ax-ie1 1382  ax-ie2 1383  ax-8 1395  ax-10 1396  ax-11 1397  ax-i12 1398  ax-bndl 1399  ax-4 1400  ax-17 1419  ax-i9 1423  ax-ial 1427  ax-i5r 1428  ax-ext 2022
This theorem depends on definitions:  df-bi 110  df-tru 1246  df-fal 1249  df-nf 1350  df-sb 1646  df-clab 2027  df-cleq 2033  df-clel 2036  df-nfc 2167  df-ne 2206  df-ral 2311  df-v 2559  df-dif 2920  df-un 2922  df-in 2924  df-ss 2931  df-nul 3225  df-sn 3381  df-pr 3382
This theorem is referenced by: (None)
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