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Theorem tpeq3 3581
Description: Equality theorem for unordered triples. (Contributed by NM, 13-Sep-2011.)
Assertion
Ref Expression
tpeq3  |-  ( A  =  B  ->  { C ,  D ,  A }  =  { C ,  D ,  B } )

Proof of Theorem tpeq3
StepHypRef Expression
1 sneq 3508 . . 3  |-  ( A  =  B  ->  { A }  =  { B } )
21uneq2d 3200 . 2  |-  ( A  =  B  ->  ( { C ,  D }  u.  { A } )  =  ( { C ,  D }  u.  { B } ) )
3 df-tp 3505 . 2  |-  { C ,  D ,  A }  =  ( { C ,  D }  u.  { A } )
4 df-tp 3505 . 2  |-  { C ,  D ,  B }  =  ( { C ,  D }  u.  { B } )
52, 3, 43eqtr4g 2175 1  |-  ( A  =  B  ->  { C ,  D ,  A }  =  { C ,  D ,  B } )
Colors of variables: wff set class
Syntax hints:    -> wi 4    = wceq 1316    u. cun 3039   {csn 3497   {cpr 3498   {ctp 3499
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-io 683  ax-5 1408  ax-7 1409  ax-gen 1410  ax-ie1 1454  ax-ie2 1455  ax-8 1467  ax-10 1468  ax-11 1469  ax-i12 1470  ax-bndl 1471  ax-4 1472  ax-17 1491  ax-i9 1495  ax-ial 1499  ax-i5r 1500  ax-ext 2099
This theorem depends on definitions:  df-bi 116  df-tru 1319  df-nf 1422  df-sb 1721  df-clab 2104  df-cleq 2110  df-clel 2113  df-nfc 2247  df-v 2662  df-un 3045  df-sn 3503  df-tp 3505
This theorem is referenced by:  tpeq3d  3584  tppreq3  3596  fztpval  9831
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