Theorem nfeld 2298

Description: Hypothesis builder for elementhood. (Contributed by Mario Carneiro, 7-Oct-2016.)

Hypotheses

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

Assertion

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

Proof of Theorem nfeld

Dummy variable y is distinct from all other variables.

Step	Hyp	Ref	Expression
1		df-clel 2136	. 2 |- ( A e. B <-> E. y ( y = A /\ y e. B ) )
2		nfv 1509	. . 3 |- F/ y ph
3		nfcvd 2283	. . . . 5 |- ( ph -> F/_ x y )
4		nfeqd.1	. . . . 5 |- ( ph -> F/_ x A )
5	3, 4	nfeqd 2297	. . . 4 |- ( ph -> F/ x y = A )
6		nfeqd.2	. . . . 5 |- ( ph -> F/_ x B )
7	6	nfcrd 2296	. . . 4 |- ( ph -> F/ x y e. B )
8	5, 7	nfand 1548	. . 3 |- ( ph -> F/ x ( y = A /\ y e. B ) )
9	2, 8	nfexd 1735	. 2 |- ( ph -> F/ x E. y ( y = A /\ y e. B ) )
10	1, 9	nfxfrd 1452	1 |- ( ph -> F/ x A e. B )

Syntax hints:   -> wi 4   /\ wa 103   = wceq 1332   F/wnf 1437   E.wex 1469   e. wcel 1481   F/_wnfc 2269

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-5 1424  ax-7 1425  ax-gen 1426  ax-ie1 1470  ax-ie2 1471  ax-4 1488  ax-17 1507  ax-ial 1515  ax-i5r 1516  ax-ext 2122

This theorem depends on definitions:  df-bi 116  df-nf 1438  df-cleq 2133  df-clel 2136  df-nfc 2271

This theorem is referenced by:  nfneld  2412  nfraldxy  2470  nfrexdxy  2471  nfreudxy  2607  nfsbc1d  2929  nfsbcd  2932  sbcrext  2990  nfbrd  3981  nfriotadxy  5746  nfixpxy  6619