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Theorem preq1i 3802
 Description: Equality inference for unordered pairs. (Contributed by NM, 19-Oct-2012.)
Hypothesis
Ref Expression
preq1i.1 A = B
Assertion
Ref Expression
preq1i {A, C} = {B, C}

Proof of Theorem preq1i
StepHypRef Expression
1 preq1i.1 . 2 A = B
2 preq1 3799 . 2 (A = B → {A, C} = {B, C})
31, 2ax-mp 8 1 {A, C} = {B, C}
 Colors of variables: wff setvar class Syntax hints:   = 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: (None)
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