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Theorem preq12 3801
 Description: Equality theorem for unordered pairs. (Contributed by NM, 19-Oct-2012.)
Assertion
Ref Expression
preq12 ((A = C B = D) → {A, B} = {C, D})

Proof of Theorem preq12
StepHypRef Expression
1 preq1 3799 . 2 (A = C → {A, B} = {C, B})
2 preq2 3800 . 2 (B = D → {C, B} = {C, D})
31, 2sylan9eq 2405 1 ((A = C B = D) → {A, B} = {C, D})
 Colors of variables: wff setvar class Syntax hints:   → wi 4   ∧ wa 358   = wceq 1642  {cpr 3738 This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-3 7  ax-mp 8  ax-gen 1546  ax-5 1557  ax-17 1616  ax-9 1654  ax-8 1675  ax-6 1729  ax-7 1734  ax-11 1746  ax-12 1925  ax-ext 2334 This theorem depends on definitions:  df-bi 177  df-or 359  df-an 360  df-nan 1288  df-tru 1319  df-ex 1542  df-nf 1545  df-sb 1649  df-clab 2340  df-cleq 2346  df-clel 2349  df-nfc 2478  df-v 2861  df-nin 3211  df-compl 3212  df-un 3214  df-sn 3741  df-pr 3742 This theorem is referenced by:  preq12i  3804  preq12d  3807  preq12b  4127  ce2  6192
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