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Theorem elab3gf 3325
Description: Membership in a class abstraction, with a weaker antecedent than elabgf 3317. (Contributed by NM, 6-Sep-2011.)
Hypotheses
Ref Expression
elab3gf.1 𝑥𝐴
elab3gf.2 𝑥𝜓
elab3gf.3 (𝑥 = 𝐴 → (𝜑𝜓))
Assertion
Ref Expression
elab3gf ((𝜓𝐴𝐵) → (𝐴 ∈ {𝑥𝜑} ↔ 𝜓))

Proof of Theorem elab3gf
StepHypRef Expression
1 elab3gf.1 . . . . 5 𝑥𝐴
2 elab3gf.2 . . . . 5 𝑥𝜓
3 elab3gf.3 . . . . 5 (𝑥 = 𝐴 → (𝜑𝜓))
41, 2, 3elabgf 3317 . . . 4 (𝐴 ∈ {𝑥𝜑} → (𝐴 ∈ {𝑥𝜑} ↔ 𝜓))
54ibi 255 . . 3 (𝐴 ∈ {𝑥𝜑} → 𝜓)
6 pm2.21 119 . . 3 𝜓 → (𝜓𝐴 ∈ {𝑥𝜑}))
75, 6impbid2 215 . 2 𝜓 → (𝐴 ∈ {𝑥𝜑} ↔ 𝜓))
81, 2, 3elabgf 3317 . 2 (𝐴𝐵 → (𝐴 ∈ {𝑥𝜑} ↔ 𝜓))
97, 8ja 172 1 ((𝜓𝐴𝐵) → (𝐴 ∈ {𝑥𝜑} ↔ 𝜓))
Colors of variables: wff setvar class
Syntax hints:  ¬ wn 3  wi 4  wb 195   = wceq 1475  wnf 1699  wcel 1977  {cab 2596  wnfc 2738
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1713  ax-4 1728  ax-5 1827  ax-6 1875  ax-7 1922  ax-10 2006  ax-11 2021  ax-12 2034  ax-13 2234  ax-ext 2590
This theorem depends on definitions:  df-bi 196  df-or 384  df-an 385  df-tru 1478  df-ex 1696  df-nf 1701  df-sb 1868  df-clab 2597  df-cleq 2603  df-clel 2606  df-nfc 2740  df-v 3175
This theorem is referenced by:  elab3g  3326
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