Theorem nfneld 2347

Description: Bound-variable hypothesis builder for negated membership. (Contributed by David Abernethy, 26-Jun-2011.) (Revised by Mario Carneiro, 7-Oct-2016.)

Hypotheses

Ref	Expression
nfneld.1	|- ( ph -> F/_ x A )
nfneld.2	|- ( ph -> F/_ x B )

Assertion

Ref	Expression
nfneld	|- ( ph -> F/ x A e/ B )

Proof of Theorem nfneld

Step	Hyp	Ref	Expression
1		df-nel 2340	. 2 |- ( A e/ B <-> -. A e. B )
2		nfneld.1	. . . 4 |- ( ph -> F/_ x A )
3		nfneld.2	. . . 4 |- ( ph -> F/_ x B )
4	2, 3	nfeld 2234	. . 3 |- ( ph -> F/ x A e. B )
5	4	nfnd 1587	. 2 |- ( ph -> F/ x -. A e. B )
6	1, 5	nfxfrd 1404	1 |- ( ph -> F/ x A e/ B )

Syntax hints:   -. wn 3   -> wi 4   F/wnf 1389   e. wcel 1433   F/_wnfc 2206   e/ wnel 2339

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 104  ax-ia2 105  ax-ia3 106  ax-in1 576  ax-in2 577  ax-5 1376  ax-7 1377  ax-gen 1378  ax-ie1 1422  ax-ie2 1423  ax-4 1440  ax-17 1459  ax-ial 1467  ax-i5r 1468  ax-ext 2063

This theorem depends on definitions:  df-bi 115  df-tru 1287  df-fal 1290  df-nf 1390  df-cleq 2074  df-clel 2077  df-nfc 2208  df-nel 2340

This theorem is referenced by: (None)