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Theorem nfintd 45057
Description: Bound-variable hypothesis builder for intersection. (Contributed by Emmett Weisz, 16-Jan-2020.)
Hypothesis
Ref Expression
nfintd.1 (𝜑𝑥𝐴)
Assertion
Ref Expression
nfintd (𝜑𝑥 𝐴)

Proof of Theorem nfintd
Dummy variables 𝑦 𝑧 are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 df-int 4864 . 2 𝐴 = {𝑦 ∣ ∀𝑧(𝑧𝐴𝑦𝑧)}
2 nfv 1916 . . 3 𝑦𝜑
3 nfv 1916 . . . 4 𝑧𝜑
4 nfintd.1 . . . . . 6 (𝜑𝑥𝐴)
54nfcrd 2971 . . . . 5 (𝜑 → Ⅎ𝑥 𝑧𝐴)
6 nfv 1916 . . . . . 6 𝑥 𝑦𝑧
76a1i 11 . . . . 5 (𝜑 → Ⅎ𝑥 𝑦𝑧)
85, 7nfimd 1896 . . . 4 (𝜑 → Ⅎ𝑥(𝑧𝐴𝑦𝑧))
93, 8nfald 2349 . . 3 (𝜑 → Ⅎ𝑥𝑧(𝑧𝐴𝑦𝑧))
102, 9nfabdw 3003 . 2 (𝜑𝑥{𝑦 ∣ ∀𝑧(𝑧𝐴𝑦𝑧)})
111, 10nfcxfrd 2981 1 (𝜑𝑥 𝐴)
Colors of variables: wff setvar class
Syntax hints:  wi 4  wal 1536  wnf 1785  wcel 2115  {cab 2802  wnfc 2962   cint 4863
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 1912  ax-6 1971  ax-7 2016  ax-8 2117  ax-9 2125  ax-10 2146  ax-11 2162  ax-12 2179  ax-ext 2796
This theorem depends on definitions:  df-bi 210  df-an 400  df-or 845  df-ex 1782  df-nf 1786  df-sb 2071  df-clab 2803  df-cleq 2817  df-clel 2896  df-nfc 2964  df-int 4864
This theorem is referenced by: (None)
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