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Theorem bj-om 14692
Description: A set is equal to ω if and only if it is the smallest inductive set. (Contributed by BJ, 30-Nov-2019.) (Proof modification is discouraged.)
Assertion
Ref Expression
bj-om (𝐴𝑉 → (𝐴 = ω ↔ (Ind 𝐴 ∧ ∀𝑥(Ind 𝑥𝐴𝑥))))
Distinct variable group:   𝑥,𝐴
Allowed substitution hint:   𝑉(𝑥)

Proof of Theorem bj-om
StepHypRef Expression
1 bj-omind 14689 . . . 4 Ind ω
2 bj-indeq 14684 . . . 4 (𝐴 = ω → (Ind 𝐴 ↔ Ind ω))
31, 2mpbiri 168 . . 3 (𝐴 = ω → Ind 𝐴)
4 vex 2741 . . . . . 6 𝑥 ∈ V
5 bj-omssind 14690 . . . . . 6 (𝑥 ∈ V → (Ind 𝑥 → ω ⊆ 𝑥))
64, 5ax-mp 5 . . . . 5 (Ind 𝑥 → ω ⊆ 𝑥)
7 sseq1 3179 . . . . 5 (𝐴 = ω → (𝐴𝑥 ↔ ω ⊆ 𝑥))
86, 7imbitrrid 156 . . . 4 (𝐴 = ω → (Ind 𝑥𝐴𝑥))
98alrimiv 1874 . . 3 (𝐴 = ω → ∀𝑥(Ind 𝑥𝐴𝑥))
103, 9jca 306 . 2 (𝐴 = ω → (Ind 𝐴 ∧ ∀𝑥(Ind 𝑥𝐴𝑥)))
11 bj-ssom 14691 . . . . . . 7 (∀𝑥(Ind 𝑥𝐴𝑥) ↔ 𝐴 ⊆ ω)
1211biimpi 120 . . . . . 6 (∀𝑥(Ind 𝑥𝐴𝑥) → 𝐴 ⊆ ω)
1312adantl 277 . . . . 5 ((Ind 𝐴 ∧ ∀𝑥(Ind 𝑥𝐴𝑥)) → 𝐴 ⊆ ω)
1413a1i 9 . . . 4 (𝐴𝑉 → ((Ind 𝐴 ∧ ∀𝑥(Ind 𝑥𝐴𝑥)) → 𝐴 ⊆ ω))
15 bj-omssind 14690 . . . . 5 (𝐴𝑉 → (Ind 𝐴 → ω ⊆ 𝐴))
1615adantrd 279 . . . 4 (𝐴𝑉 → ((Ind 𝐴 ∧ ∀𝑥(Ind 𝑥𝐴𝑥)) → ω ⊆ 𝐴))
1714, 16jcad 307 . . 3 (𝐴𝑉 → ((Ind 𝐴 ∧ ∀𝑥(Ind 𝑥𝐴𝑥)) → (𝐴 ⊆ ω ∧ ω ⊆ 𝐴)))
18 eqss 3171 . . 3 (𝐴 = ω ↔ (𝐴 ⊆ ω ∧ ω ⊆ 𝐴))
1917, 18imbitrrdi 162 . 2 (𝐴𝑉 → ((Ind 𝐴 ∧ ∀𝑥(Ind 𝑥𝐴𝑥)) → 𝐴 = ω))
2010, 19impbid2 143 1 (𝐴𝑉 → (𝐴 = ω ↔ (Ind 𝐴 ∧ ∀𝑥(Ind 𝑥𝐴𝑥))))
Colors of variables: wff set class
Syntax hints:  wi 4  wa 104  wb 105  wal 1351   = wceq 1353  wcel 2148  Vcvv 2738  wss 3130  ωcom 4590  Ind wind 14681
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-in1 614  ax-in2 615  ax-io 709  ax-5 1447  ax-7 1448  ax-gen 1449  ax-ie1 1493  ax-ie2 1494  ax-8 1504  ax-10 1505  ax-11 1506  ax-i12 1507  ax-bndl 1509  ax-4 1510  ax-17 1526  ax-i9 1530  ax-ial 1534  ax-i5r 1535  ax-13 2150  ax-14 2151  ax-ext 2159  ax-nul 4130  ax-pr 4210  ax-un 4434  ax-bd0 14568  ax-bdor 14571  ax-bdex 14574  ax-bdeq 14575  ax-bdel 14576  ax-bdsb 14577  ax-bdsep 14639
This theorem depends on definitions:  df-bi 117  df-tru 1356  df-nf 1461  df-sb 1763  df-clab 2164  df-cleq 2170  df-clel 2173  df-nfc 2308  df-ral 2460  df-rex 2461  df-rab 2464  df-v 2740  df-dif 3132  df-un 3134  df-in 3136  df-ss 3143  df-nul 3424  df-sn 3599  df-pr 3600  df-uni 3811  df-int 3846  df-suc 4372  df-iom 4591  df-bdc 14596  df-bj-ind 14682
This theorem is referenced by:  bj-2inf  14693  bj-inf2vn  14729  bj-inf2vn2  14730
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