Theorem nfrexw 2589

Description: Not-free for restricted existential quantification where 𝑥 and 𝑦 are distinct. See nfrexya 2591 for a version with 𝑦 and 𝐴 distinct instead. (Contributed by Jim Kingdon, 30-May-2018.)

Hypotheses

Ref	Expression
nfralxy.1	⊢ Ⅎ𝑥𝐴
nfralxy.2	⊢ Ⅎ𝑥𝜑

Assertion

Ref	Expression
nfrexw	⊢ Ⅎ𝑥∃𝑦 ∈ 𝐴 𝜑

Distinct variable group:   𝑥,𝑦

Allowed substitution hints:   𝜑(𝑥, 𝑦)   𝐴(𝑥, 𝑦)

Proof of Theorem nfrexw

Step	Hyp	Ref	Expression
1		nftru 1519	. . 3 ⊢ Ⅎ𝑦⊤
2		nfralxy.1	. . . 4 ⊢ Ⅎ𝑥𝐴
3	2	a1i 9	. . 3 ⊢ (⊤ → Ⅎ𝑥𝐴)
4		nfralxy.2	. . . 4 ⊢ Ⅎ𝑥𝜑
5	4	a1i 9	. . 3 ⊢ (⊤ → Ⅎ𝑥𝜑)
6	1, 3, 5	nfrexdxy 2584	. 2 ⊢ (⊤ → Ⅎ𝑥∃𝑦 ∈ 𝐴 𝜑)
7	6	mptru 1411	1 ⊢ Ⅎ𝑥∃𝑦 ∈ 𝐴 𝜑

This proof depends on syntax axioms:  ⊤wtru 1403  Ⅎwnf 1513  Ⅎwnfc 2379  ∃wrex 2529

This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-5 1500  ax-7 1501  ax-gen 1502  ax-ie1 1546  ax-ie2 1547  ax-4 1563  ax-17 1579  ax-ial 1587  ax-i5r 1588  ax-ext 2220

This proof depends on definitions:  df-bi 117  df-tru 1405  df-nf 1514  df-cleq 2231  df-clel 2234  df-nfc 2381  df-rex 2534

This theorem is used by:  r19.12  2657  sbcrext  3129  nfuni  3941  nfiunxy  4038  rexxpf  4927  abrexex2g  6349  abrexex2  6353  nfrecs  6578  nfwrd  11335  fimaxre2  11995  nfsum  12125  nfcprod1  12323  nfcprod  12324  bezoutlemmain  12777  ctiunctlemfo  13332  bj-findis  17017  strcollnfALT  17024  nfrals  17157