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Theorem nfreuw 3327
Description: Bound-variable hypothesis builder for restricted unique existence. Version of nfreu 3329 with a disjoint variable condition, which does not require ax-13 2379. (Contributed by NM, 30-Oct-2010.) (Revised by Gino Giotto, 10-Jan-2024.)
Hypotheses
Ref Expression
nfreuw.1 𝑥𝐴
nfreuw.2 𝑥𝜑
Assertion
Ref Expression
nfreuw 𝑥∃!𝑦𝐴 𝜑
Distinct variable group:   𝑥,𝑦
Allowed substitution hints:   𝜑(𝑥,𝑦)   𝐴(𝑥,𝑦)

Proof of Theorem nfreuw
StepHypRef Expression
1 df-reu 3113 . . 3 (∃!𝑦𝐴 𝜑 ↔ ∃!𝑦(𝑦𝐴𝜑))
2 nftru 1806 . . . 4 𝑦
3 nfcvd 2956 . . . . . 6 (⊤ → 𝑥𝑦)
4 nfreuw.1 . . . . . . 7 𝑥𝐴
54a1i 11 . . . . . 6 (⊤ → 𝑥𝐴)
63, 5nfeld 2966 . . . . 5 (⊤ → Ⅎ𝑥 𝑦𝐴)
7 nfreuw.2 . . . . . 6 𝑥𝜑
87a1i 11 . . . . 5 (⊤ → Ⅎ𝑥𝜑)
96, 8nfand 1898 . . . 4 (⊤ → Ⅎ𝑥(𝑦𝐴𝜑))
102, 9nfeudw 2652 . . 3 (⊤ → Ⅎ𝑥∃!𝑦(𝑦𝐴𝜑))
111, 10nfxfrd 1855 . 2 (⊤ → Ⅎ𝑥∃!𝑦𝐴 𝜑)
1211mptru 1545 1 𝑥∃!𝑦𝐴 𝜑
Colors of variables: wff setvar class
Syntax hints:  wa 399  wtru 1539  wnf 1785  wcel 2111  ∃!weu 2628  wnfc 2936  ∃!wreu 3108
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1797  ax-4 1811  ax-5 1911  ax-6 1970  ax-7 2015  ax-8 2113  ax-9 2121  ax-10 2142  ax-11 2158  ax-12 2175  ax-ext 2770
This theorem depends on definitions:  df-bi 210  df-an 400  df-or 845  df-tru 1541  df-ex 1782  df-nf 1786  df-mo 2598  df-eu 2629  df-cleq 2791  df-clel 2870  df-nfc 2938  df-reu 3113
This theorem is referenced by:  sbcreu  3805  reuccatpfxs1  14100  2reu7  43667  2reu8  43668
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