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Theorem bj-vtoclg1f1 34301
 Description: The FOL content of vtoclg1f 3552 (hence not using ax-ext 2796, df-cleq 2817, df-nfc 2964, df-v 3482). Note the weakened "major" hypothesis and the disjoint variable condition between 𝑥 and 𝐴 (needed since the nonfreeness quantifier for classes is not available without ax-ext 2796; as a byproduct, this dispenses with ax-11 2162 and ax-13 2392). (Contributed by BJ, 30-Apr-2019.) (Proof modification is discouraged.)
Hypotheses
Ref Expression
bj-vtoclg1f1.nf 𝑥𝜓
bj-vtoclg1f1.maj (𝑥 = 𝐴 → (𝜑𝜓))
bj-vtoclg1f1.min 𝜑
Assertion
Ref Expression
bj-vtoclg1f1 (∃𝑦 𝑦 = 𝐴𝜓)
Distinct variable groups:   𝑥,𝐴   𝑦,𝐴
Allowed substitution hints:   𝜑(𝑥,𝑦)   𝜓(𝑥,𝑦)

Proof of Theorem bj-vtoclg1f1
StepHypRef Expression
1 bj-denotes 34254 . 2 (∃𝑦 𝑦 = 𝐴 ↔ ∃𝑥 𝑥 = 𝐴)
2 bj-vtoclg1f1.nf . . 3 𝑥𝜓
3 bj-vtoclg1f1.maj . . 3 (𝑥 = 𝐴 → (𝜑𝜓))
4 bj-vtoclg1f1.min . . 3 𝜑
52, 3, 4bj-exlimmpi 34296 . 2 (∃𝑥 𝑥 = 𝐴𝜓)
61, 5sylbi 220 1 (∃𝑦 𝑦 = 𝐴𝜓)
 Colors of variables: wff setvar class Syntax hints:   → wi 4   = wceq 1538  ∃wex 1781  Ⅎwnf 1785 This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1797  ax-4 1811  ax-5 1912  ax-6 1971  ax-7 2016  ax-8 2117  ax-12 2179 This theorem depends on definitions:  df-bi 210  df-an 400  df-tru 1541  df-ex 1782  df-nf 1786  df-sb 2071  df-clab 2803  df-clel 2896 This theorem is referenced by: (None)
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