Theorem nfeld 2390

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

Hypotheses

Ref	Expression
nfeqd.1	⊢ (𝜑 → Ⅎ𝑥𝐴)
nfeqd.2	⊢ (𝜑 → Ⅎ𝑥𝐵)

Assertion

Ref	Expression
nfeld	⊢ (𝜑 → Ⅎ𝑥 𝐴 ∈ 𝐵)

Proof of Theorem nfeld

Dummy variable 𝑦 is distinct from all other variables.

Step	Hyp	Ref	Expression
1		df-clel 2227	. 2 ⊢ (𝐴 ∈ 𝐵 ↔ ∃𝑦(𝑦 = 𝐴 ∧ 𝑦 ∈ 𝐵))
2		nfv 1576	. . 3 ⊢ Ⅎ𝑦𝜑
3		nfcvd 2375	. . . . 5 ⊢ (𝜑 → Ⅎ𝑥𝑦)
4		nfeqd.1	. . . . 5 ⊢ (𝜑 → Ⅎ𝑥𝐴)
5	3, 4	nfeqd 2389	. . . 4 ⊢ (𝜑 → Ⅎ𝑥 𝑦 = 𝐴)
6		nfeqd.2	. . . . 5 ⊢ (𝜑 → Ⅎ𝑥𝐵)
7	6	nfcrd 2388	. . . 4 ⊢ (𝜑 → Ⅎ𝑥 𝑦 ∈ 𝐵)
8	5, 7	nfand 1616	. . 3 ⊢ (𝜑 → Ⅎ𝑥(𝑦 = 𝐴 ∧ 𝑦 ∈ 𝐵))
9	2, 8	nfexd 1809	. 2 ⊢ (𝜑 → Ⅎ𝑥∃𝑦(𝑦 = 𝐴 ∧ 𝑦 ∈ 𝐵))
10	1, 9	nfxfrd 1523	1 ⊢ (𝜑 → Ⅎ𝑥 𝐴 ∈ 𝐵)

Syntax hints:   → wi 4   ∧ wa 104   = wceq 1397  Ⅎwnf 1508  ∃wex 1540   ∈ wcel 2202  Ⅎwnfc 2361

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-5 1495  ax-7 1496  ax-gen 1497  ax-ie1 1541  ax-ie2 1542  ax-4 1558  ax-17 1574  ax-ial 1582  ax-i5r 1583  ax-ext 2213

This theorem depends on definitions:  df-bi 117  df-nf 1509  df-cleq 2224  df-clel 2227  df-nfc 2363

This theorem is referenced by:  nfneld  2505  nfraldw  2564  nfraldxy  2565  nfrexdxy  2566  nfreudxy  2707  nfsbc1d  3048  nfsbcd  3051  sbcrext  3109  nfsbcdw  3161  nfbrd  4134  nfriotadxy  5979  nfixpxy  6885