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Theorem nfnfcALT 2804
 Description: Alternate proof of nfnfc 2803. Shorter but requiring more axioms. (Contributed by Mario Carneiro, 11-Aug-2016.) (Proof modification is discouraged.) (New usage is discouraged.)
Hypothesis
Ref Expression
nfnfc.1 𝑥𝐴
Assertion
Ref Expression
nfnfcALT 𝑥𝑦𝐴

Proof of Theorem nfnfcALT
Dummy variable 𝑧 is distinct from all other variables.
StepHypRef Expression
1 df-nfc 2782 . 2 (𝑦𝐴 ↔ ∀𝑧𝑦 𝑧𝐴)
2 nfnfc.1 . . . . 5 𝑥𝐴
32nfcri 2787 . . . 4 𝑥 𝑧𝐴
43nfnf 2196 . . 3 𝑥𝑦 𝑧𝐴
54nfal 2191 . 2 𝑥𝑧𝑦 𝑧𝐴
61, 5nfxfr 1819 1 𝑥𝑦𝐴
 Colors of variables: wff setvar class Syntax hints:  ∀wal 1521  Ⅎwnf 1748   ∈ wcel 2030  Ⅎwnfc 2780 This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1762  ax-4 1777  ax-5 1879  ax-6 1945  ax-7 1981  ax-9 2039  ax-10 2059  ax-11 2074  ax-12 2087  ax-13 2282  ax-ext 2631 This theorem depends on definitions:  df-bi 197  df-or 384  df-an 385  df-tru 1526  df-ex 1745  df-nf 1750  df-sb 1938  df-cleq 2644  df-clel 2647  df-nfc 2782 This theorem is referenced by: (None)
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