Theorem elabd 2964

Description: Explicit demonstration the class {𝑥 ∣ 𝜓} is not empty by the example 𝑋. (Contributed by RP, 12-Aug-2020.)

Hypotheses

Ref	Expression
elab.xex	⊢ (𝜑 → 𝑋 ∈ V)
elab.xmaj	⊢ (𝜑 → 𝜒)
elab.xsub	⊢ (𝑥 = 𝑋 → (𝜓 ↔ 𝜒))

Assertion

Ref	Expression
elabd	⊢ (𝜑 → ∃𝑥𝜓)

Distinct variable groups:   𝜒,𝑥   𝑥,𝑋

Allowed substitution hints:   𝜑(𝑥)   𝜓(𝑥)

Proof of Theorem elabd

Step	Hyp	Ref	Expression
1		elab.xex	. 2 ⊢ (𝜑 → 𝑋 ∈ V)
2		elab.xmaj	. 2 ⊢ (𝜑 → 𝜒)
3		elab.xsub	. . 3 ⊢ (𝑥 = 𝑋 → (𝜓 ↔ 𝜒))
4	3	spcegv 2907	. 2 ⊢ (𝑋 ∈ V → (𝜒 → ∃𝑥𝜓))
5	1, 2, 4	sylc 62	1 ⊢ (𝜑 → ∃𝑥𝜓)

Syntax hints:   → wi 4   ↔ wb 105   = wceq 1398  ∃wex 1541   ∈ wcel 2205  Vcvv 2815

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-io 717  ax-5 1496  ax-7 1497  ax-gen 1498  ax-ie1 1542  ax-ie2 1543  ax-8 1553  ax-10 1554  ax-11 1555  ax-i12 1556  ax-bndl 1558  ax-4 1559  ax-17 1575  ax-i9 1579  ax-ial 1583  ax-i5r 1584  ax-ext 2216

This theorem depends on definitions:  df-bi 117  df-tru 1401  df-nf 1510  df-sb 1812  df-clab 2221  df-cleq 2227  df-clel 2230  df-nfc 2375  df-v 2817

This theorem is referenced by:  uchoice  6333  elmpom  6436  en2prd  7061  dom1o  7071  ntrivcvgap0  12243  ssomct  13217  wlkvtxiedg  16389  wlkvtxiedgg  16390  dceqnconst  16895  dcapnconst  16896  gfsumval  16911