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Theorem orddisj 4557
Description: An ordinal class and its singleton are disjoint. (Contributed by NM, 19-May-1998.)
Assertion
Ref Expression
orddisj  |-  ( Ord 
A  ->  ( A  i^i  { A } )  =  (/) )

Proof of Theorem orddisj
StepHypRef Expression
1 ordirr 4553 . 2  |-  ( Ord 
A  ->  -.  A  e.  A )
2 disjsn 3666 . 2  |-  ( ( A  i^i  { A } )  =  (/)  <->  -.  A  e.  A )
31, 2sylibr 134 1  |-  ( Ord 
A  ->  ( A  i^i  { A } )  =  (/) )
Colors of variables: wff set class
Syntax hints:   -. wn 3    -> wi 4    = wceq 1363    e. wcel 2158    i^i cin 3140   (/)c0 3434   {csn 3604   Ord word 4374
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 710  ax-5 1457  ax-7 1458  ax-gen 1459  ax-ie1 1503  ax-ie2 1504  ax-8 1514  ax-10 1515  ax-11 1516  ax-i12 1517  ax-bndl 1519  ax-4 1520  ax-17 1536  ax-i9 1540  ax-ial 1544  ax-i5r 1545  ax-ext 2169  ax-setind 4548
This theorem depends on definitions:  df-bi 117  df-3an 981  df-tru 1366  df-fal 1369  df-nf 1471  df-sb 1773  df-clab 2174  df-cleq 2180  df-clel 2183  df-nfc 2318  df-ne 2358  df-ral 2470  df-v 2751  df-dif 3143  df-in 3147  df-nul 3435  df-sn 3610
This theorem is referenced by:  orddif  4558  phplem2  6866  ennnfonelemhf1o  12427
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