Theorem spcimegf 3527

Description: Existential specialization, using implicit substitution. (Contributed by Mario Carneiro, 4-Jan-2017.)

Hypotheses

Ref	Expression
spcimgf.1	⊢ Ⅎ𝑥𝐴
spcimgf.2	⊢ Ⅎ𝑥𝜓
spcimegf.3	⊢ (𝑥 = 𝐴 → (𝜓 → 𝜑))

Assertion

Ref	Expression
spcimegf	⊢ (𝐴 ∈ 𝑉 → (𝜓 → ∃𝑥𝜑))

Proof of Theorem spcimegf

Step	Hyp	Ref	Expression
1		spcimgf.1	. . . 4 ⊢ Ⅎ𝑥𝐴
2		spcimgf.2	. . . . 5 ⊢ Ⅎ𝑥𝜓
3	2	nfn 1863	. . . 4 ⊢ Ⅎ𝑥 ¬ 𝜓
4		spcimegf.3	. . . . 5 ⊢ (𝑥 = 𝐴 → (𝜓 → 𝜑))
5	4	con3d 152	. . . 4 ⊢ (𝑥 = 𝐴 → (¬ 𝜑 → ¬ 𝜓))
6	1, 3, 5	spcimgf 3526	. . 3 ⊢ (𝐴 ∈ 𝑉 → (∀𝑥 ¬ 𝜑 → ¬ 𝜓))
7	6	con2d 134	. 2 ⊢ (𝐴 ∈ 𝑉 → (𝜓 → ¬ ∀𝑥 ¬ 𝜑))
8		df-ex 1786	. 2 ⊢ (∃𝑥𝜑 ↔ ¬ ∀𝑥 ¬ 𝜑)
9	7, 8	syl6ibr 251	1 ⊢ (𝐴 ∈ 𝑉 → (𝜓 → ∃𝑥𝜑))

Syntax hints:  ¬ wn 3   → wi 4  ∀wal 1539   = wceq 1541  ∃wex 1785  Ⅎwnf 1789   ∈ wcel 2109  Ⅎwnfc 2888

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1801  ax-4 1815  ax-5 1916  ax-6 1974  ax-7 2014  ax-8 2111  ax-9 2119  ax-10 2140  ax-11 2157  ax-12 2174  ax-ext 2710

This theorem depends on definitions:  df-bi 206  df-an 396  df-or 844  df-tru 1544  df-ex 1786  df-nf 1790  df-sb 2071  df-clab 2717  df-cleq 2731  df-clel 2817  df-nfc 2890  df-v 3432

This theorem is referenced by: (None)