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Theorem nfraldw 2582
Description: Not-free for restricted universal quantification where 𝑥 and 𝑦 are distinct. See nfraldya 2585 for a version with 𝑦 and 𝐴 distinct instead. (Contributed by NM, 15-Feb-2013.) (Revised by GG, 10-Jan-2024.)
Hypotheses
Ref Expression
nfraldw.1 Ⅎ𝑦𝜑
nfraldw.2 (𝜑 → Ⅎ𝑥𝐴)
nfraldw.3 (𝜑 → Ⅎ𝑥𝜓)
Assertion
Ref Expression
nfraldw (𝜑 → Ⅎ𝑥∀𝑦 ∈ 𝐴 𝜓)
Distinct variable group:   𝑥,𝑦
Allowed substitution hints:   𝜑(𝑥, 𝑦)   𝜓(𝑥, 𝑦)   𝐴(𝑥, 𝑦)

Proof of Theorem nfraldw
StepHypRef Expression
1 df-ral 2533 . 2 (∀𝑦 ∈ 𝐴 𝜓 ↔ ∀𝑦(𝑦 ∈ 𝐴 → 𝜓))
2 nfraldw.1 . . 3 Ⅎ𝑦𝜑
3 nfcvd 2393 . . . . 5 (𝜑 → Ⅎ𝑥𝑦)
4 nfraldw.2 . . . . 5 (𝜑 → Ⅎ𝑥𝐴)
53, 4nfeld 2408 . . . 4 (𝜑 → Ⅎ𝑥 𝑦 ∈ 𝐴)
6 nfraldw.3 . . . 4 (𝜑 → Ⅎ𝑥𝜓)
75, 6nfimd 1638 . . 3 (𝜑 → Ⅎ𝑥(𝑦 ∈ 𝐴 → 𝜓))
82, 7nfald 1813 . 2 (𝜑 → Ⅎ𝑥∀𝑦(𝑦 ∈ 𝐴 → 𝜓))
91, 8nfxfrd 1528 1 (𝜑 → Ⅎ𝑥∀𝑦 ∈ 𝐴 𝜓)
Colors of variables:    wff set class
This proof depends on syntax axioms:   → wi 4  ∀wal 1400  Ⅎwnf 1513   ∈ wcel 2209  Ⅎwnfc 2379  ∀wral 2528
This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-5 1500  ax-7 1501  ax-gen 1502  ax-ie1 1546  ax-ie2 1547  ax-4 1563  ax-17 1579  ax-ial 1587  ax-i5r 1588  ax-ext 2220
This proof depends on definitions:  df-bi 117  df-nf 1514  df-cleq 2231  df-clel 2234  df-nfc 2381  df-ral 2533
This theorem is used by:  nfralw  2587
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