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Theorem nfrabw 2712
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 2517 . 2 {𝑦𝐴𝜑} = {𝑦 ∣ (𝑦𝐴𝜑)}
2 nfrabw.2 . . . . 5 𝑥𝐴
32nfcri 2366 . . . 4 𝑥 𝑦𝐴
4 nfrabw.1 . . . 4 𝑥𝜑
53, 4nfan 1611 . . 3 𝑥(𝑦𝐴𝜑)
65nfab 2377 . 2 𝑥{𝑦 ∣ (𝑦𝐴𝜑)}
71, 6nfcxfr 2369 1 𝑥{𝑦𝐴𝜑}
Colors of variables: wff set class
Syntax hints:  wa 104  wnf 1506  wcel 2200  {cab 2215  wnfc 2359  {crab 2512
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 714  ax-5 1493  ax-7 1494  ax-gen 1495  ax-ie1 1539  ax-ie2 1540  ax-8 1550  ax-10 1551  ax-11 1552  ax-i12 1553  ax-bndl 1555  ax-4 1556  ax-17 1572  ax-i9 1576  ax-ial 1580  ax-i5r 1581  ax-ext 2211
This theorem depends on definitions:  df-bi 117  df-nf 1507  df-sb 1809  df-clab 2216  df-cleq 2222  df-clel 2225  df-nfc 2361  df-rab 2517
This theorem is referenced by:  nfdif  3325  nfin  3410  nfse  4432  elfvmptrab1  5731  elovmporab  6211  elovmporab1w  6212  mpoxopoveq  6392  nfsup  7167  caucvgprprlemaddq  7903  ctiunct  13019
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