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Theorem setindel 4659
Description: -Induction in terms of membership in a class. (Contributed by Mario Carneiro and Jim Kingdon, 22-Oct-2018.)
Assertion
Ref Expression
setindel (∀𝑥(∀𝑦(𝑦𝑥𝑦𝑆) → 𝑥𝑆) → 𝑆 = V)
Distinct variable group:   𝑥,𝑦,𝑆

Proof of Theorem setindel
StepHypRef Expression
1 clelsb1 2337 . . . . . . 7 ([𝑦 / 𝑥]𝑥𝑆𝑦𝑆)
21ralbii 2548 . . . . . 6 (∀𝑦𝑥 [𝑦 / 𝑥]𝑥𝑆 ↔ ∀𝑦𝑥 𝑦𝑆)
3 df-ral 2525 . . . . . 6 (∀𝑦𝑥 𝑦𝑆 ↔ ∀𝑦(𝑦𝑥𝑦𝑆))
42, 3bitri 184 . . . . 5 (∀𝑦𝑥 [𝑦 / 𝑥]𝑥𝑆 ↔ ∀𝑦(𝑦𝑥𝑦𝑆))
54imbi1i 238 . . . 4 ((∀𝑦𝑥 [𝑦 / 𝑥]𝑥𝑆𝑥𝑆) ↔ (∀𝑦(𝑦𝑥𝑦𝑆) → 𝑥𝑆))
65albii 1519 . . 3 (∀𝑥(∀𝑦𝑥 [𝑦 / 𝑥]𝑥𝑆𝑥𝑆) ↔ ∀𝑥(∀𝑦(𝑦𝑥𝑦𝑆) → 𝑥𝑆))
7 ax-setind 4658 . . 3 (∀𝑥(∀𝑦𝑥 [𝑦 / 𝑥]𝑥𝑆𝑥𝑆) → ∀𝑥 𝑥𝑆)
86, 7sylbir 135 . 2 (∀𝑥(∀𝑦(𝑦𝑥𝑦𝑆) → 𝑥𝑆) → ∀𝑥 𝑥𝑆)
9 eqv 3527 . 2 (𝑆 = V ↔ ∀𝑥 𝑥𝑆)
108, 9sylibr 134 1 (∀𝑥(∀𝑦(𝑦𝑥𝑦𝑆) → 𝑥𝑆) → 𝑆 = V)
Colors of variables: wff set class
Syntax hints:  wi 4  wal 1396   = wceq 1398  [wsb 1811  wcel 2203  wral 2520  Vcvv 2812
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 2214  ax-setind 4658
This theorem depends on definitions:  df-bi 117  df-tru 1401  df-nf 1510  df-sb 1812  df-clab 2219  df-cleq 2225  df-clel 2228  df-ral 2525  df-v 2814
This theorem is referenced by:  setind  4660
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