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Theorem reueq1 2687
Description: Equality theorem for restricted unique existential quantifier. (Contributed by NM, 5-Apr-2004.)
Assertion
Ref Expression
reueq1 (𝐴 = 𝐵 → (∃!𝑥𝐴 𝜑 ↔ ∃!𝑥𝐵 𝜑))
Distinct variable groups:   𝑥,𝐴   𝑥,𝐵
Allowed substitution hint:   𝜑(𝑥)

Proof of Theorem reueq1
StepHypRef Expression
1 nfcv 2331 . 2 𝑥𝐴
2 nfcv 2331 . 2 𝑥𝐵
31, 2reueq1f 2683 1 (𝐴 = 𝐵 → (∃!𝑥𝐴 𝜑 ↔ ∃!𝑥𝐵 𝜑))
Colors of variables: wff set class
Syntax hints:  wi 4  wb 105   = wceq 1363  ∃!wreu 2469
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-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 2170
This theorem depends on definitions:  df-bi 117  df-tru 1366  df-nf 1471  df-sb 1773  df-eu 2040  df-cleq 2181  df-clel 2184  df-nfc 2320  df-reu 2474
This theorem is referenced by:  reueqd  2695  ringideu  13331
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