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Theorem nfrabw 2713
Description: A variable not free in a wff remains so in a restricted class abstraction. (Contributed by Jim Kingdon, 19-Jul-2018.)
Hypotheses
Ref Expression
nfrabw.1 𝑥𝜑
nfrabw.2 𝑥𝐴
Assertion
Ref Expression
nfrabw 𝑥{𝑦𝐴𝜑}
Distinct variable group:   𝑥,𝑦
Allowed substitution hints:   𝜑(𝑥,𝑦)   𝐴(𝑥,𝑦)

Proof of Theorem nfrabw
StepHypRef Expression
1 df-rab 2518 . 2 {𝑦𝐴𝜑} = {𝑦 ∣ (𝑦𝐴𝜑)}
2 nfrabw.2 . . . . 5 𝑥𝐴
32nfcri 2367 . . . 4 𝑥 𝑦𝐴
4 nfrabw.1 . . . 4 𝑥𝜑
53, 4nfan 1613 . . 3 𝑥(𝑦𝐴𝜑)
65nfab 2378 . 2 𝑥{𝑦 ∣ (𝑦𝐴𝜑)}
71, 6nfcxfr 2370 1 𝑥{𝑦𝐴𝜑}
Colors of variables: wff set class
Syntax hints:  wa 104  wnf 1508  wcel 2201  {cab 2216  wnfc 2360  {crab 2513
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 716  ax-5 1495  ax-7 1496  ax-gen 1497  ax-ie1 1541  ax-ie2 1542  ax-8 1552  ax-10 1553  ax-11 1554  ax-i12 1555  ax-bndl 1557  ax-4 1558  ax-17 1574  ax-i9 1578  ax-ial 1582  ax-i5r 1583  ax-ext 2212
This theorem depends on definitions:  df-bi 117  df-nf 1509  df-sb 1810  df-clab 2217  df-cleq 2223  df-clel 2226  df-nfc 2362  df-rab 2518
This theorem is referenced by:  nfdif  3327  nfin  3412  nfse  4440  elfvmptrab1  5744  elovmporab  6227  elovmporab1w  6228  mpoxopoveq  6411  nfsup  7196  caucvgprprlemaddq  7933  ctiunct  13084
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