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Theorem nfsab 2717
Description: Bound-variable hypothesis builder for a class abstraction. (Contributed by Mario Carneiro, 11-Aug-2016.) Add disjoint variable condition to avoid ax-13 2366. See nfsabg 2718 for a less restrictive version requiring more axioms. (Revised by Gino Giotto, 20-Jan-2024.)
Hypothesis
Ref Expression
nfsab.1 𝑥𝜑
Assertion
Ref Expression
nfsab 𝑥 𝑧 ∈ {𝑦𝜑}
Distinct variable groups:   𝑥,𝑦   𝑥,𝑧
Allowed substitution hints:   𝜑(𝑥,𝑦,𝑧)

Proof of Theorem nfsab
StepHypRef Expression
1 nfsab.1 . . . 4 𝑥𝜑
21nf5ri 2181 . . 3 (𝜑 → ∀𝑥𝜑)
32hbab 2715 . 2 (𝑧 ∈ {𝑦𝜑} → ∀𝑥 𝑧 ∈ {𝑦𝜑})
43nf5i 2135 1 𝑥 𝑧 ∈ {𝑦𝜑}
Colors of variables: wff setvar class
Syntax hints:  wnf 1778  wcel 2099  {cab 2704
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1790  ax-4 1804  ax-5 1906  ax-6 1964  ax-7 2004  ax-10 2130  ax-11 2147  ax-12 2164
This theorem depends on definitions:  df-bi 206  df-ex 1775  df-nf 1779  df-sb 2061  df-clab 2705
This theorem is referenced by:  nfab  2904  oaun3lem1  42726  upbdrech  44610  ssfiunibd  44614
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