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Theorem preq2i 3574
Description: Equality inference for unordered pairs. (Contributed by NM, 19-Oct-2012.)
Hypothesis
Ref Expression
preq1i.1 𝐴 = 𝐵
Assertion
Ref Expression
preq2i {𝐶, 𝐴} = {𝐶, 𝐵}

Proof of Theorem preq2i
StepHypRef Expression
1 preq1i.1 . 2 𝐴 = 𝐵
2 preq2 3571 . 2 (𝐴 = 𝐵 → {𝐶, 𝐴} = {𝐶, 𝐵})
31, 2ax-mp 5 1 {𝐶, 𝐴} = {𝐶, 𝐵}
Colors of variables: wff set class
Syntax hints:   = wceq 1316  {cpr 3498
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-pr 3504
This theorem is referenced by:  opid  3693  funopg  5127  df2o2  6296  fzprval  9830  fzo0to2pr  9963  fzo0to42pr  9965  2strstr1g  11989
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