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Theorem nfss 2938
 Description: If is not free in and , it is not free in . (Contributed by NM, 27-Dec-1996.)
Hypotheses
Ref Expression
dfss2f.1
dfss2f.2
Assertion
Ref Expression
nfss

Proof of Theorem nfss
StepHypRef Expression
1 dfss2f.1 . . 3
2 dfss2f.2 . . 3
31, 2dfss3f 2937 . 2
4 nfra1 2355 . 2
53, 4nfxfr 1363 1
 Colors of variables: wff set class Syntax hints:  wnf 1349   wcel 1393  wnfc 2165  wral 2306   wss 2917 This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 99  ax-ia2 100  ax-ia3 101  ax-io 630  ax-5 1336  ax-7 1337  ax-gen 1338  ax-ie1 1382  ax-ie2 1383  ax-8 1395  ax-10 1396  ax-11 1397  ax-i12 1398  ax-bndl 1399  ax-4 1400  ax-17 1419  ax-i9 1423  ax-ial 1427  ax-i5r 1428  ax-ext 2022 This theorem depends on definitions:  df-bi 110  df-nf 1350  df-sb 1646  df-clab 2027  df-cleq 2033  df-clel 2036  df-nfc 2167  df-ral 2311  df-in 2924  df-ss 2931 This theorem is referenced by:  nfpw  3371  ssiun2s  3701  triun  3867  ssopab2b  4013  nffrfor  4085  tfis  4306  nfrel  4425  nffun  4924  nff  5043  fvmptssdm  5255  ssoprab2b  5562  nfsum1  9875  nfsum  9876
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