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Theorem nfrabw 2692
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 2497 . 2 {𝑦𝐴𝜑} = {𝑦 ∣ (𝑦𝐴𝜑)}
2 nfrabw.2 . . . . 5 𝑥𝐴
32nfcri 2346 . . . 4 𝑥 𝑦𝐴
4 nfrabw.1 . . . 4 𝑥𝜑
53, 4nfan 1591 . . 3 𝑥(𝑦𝐴𝜑)
65nfab 2357 . 2 𝑥{𝑦 ∣ (𝑦𝐴𝜑)}
71, 6nfcxfr 2349 1 𝑥{𝑦𝐴𝜑}
Colors of variables: wff set class
Syntax hints:  wa 104  wnf 1486  wcel 2180  {cab 2195  wnfc 2339  {crab 2492
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 713  ax-5 1473  ax-7 1474  ax-gen 1475  ax-ie1 1519  ax-ie2 1520  ax-8 1530  ax-10 1531  ax-11 1532  ax-i12 1533  ax-bndl 1535  ax-4 1536  ax-17 1552  ax-i9 1556  ax-ial 1560  ax-i5r 1561  ax-ext 2191
This theorem depends on definitions:  df-bi 117  df-nf 1487  df-sb 1789  df-clab 2196  df-cleq 2202  df-clel 2205  df-nfc 2341  df-rab 2497
This theorem is referenced by:  nfdif  3305  nfin  3390  nfse  4409  elfvmptrab1  5702  elovmporab  6176  elovmporab1w  6177  mpoxopoveq  6356  nfsup  7127  caucvgprprlemaddq  7863  ctiunct  12977
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