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Theorem nfsn 3784
 Description: Bound-variable hypothesis builder for singletons. (Contributed by NM, 14-Nov-1995.)
Hypothesis
Ref Expression
nfsn.1 xA
Assertion
Ref Expression
nfsn x{A}

Proof of Theorem nfsn
StepHypRef Expression
1 dfsn2 3747 . 2 {A} = {A, A}
2 nfsn.1 . . 3 xA
32, 2nfpr 3773 . 2 x{A, A}
41, 3nfcxfr 2486 1 x{A}
 Colors of variables: wff setvar class Syntax hints:  Ⅎwnfc 2476  {csn 3737  {cpr 3738 This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-3 7  ax-mp 8  ax-gen 1546  ax-5 1557  ax-17 1616  ax-9 1654  ax-8 1675  ax-6 1729  ax-7 1734  ax-11 1746  ax-12 1925  ax-ext 2334 This theorem depends on definitions:  df-bi 177  df-or 359  df-an 360  df-nan 1288  df-tru 1319  df-ex 1542  df-nf 1545  df-sb 1649  df-clab 2340  df-cleq 2346  df-clel 2349  df-nfc 2478  df-v 2861  df-nin 3211  df-compl 3212  df-un 3214  df-sn 3741  df-pr 3742 This theorem is referenced by:  nfopk  4068  sniota  4369
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