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| Mirrors > Home > ILE Home > Th. List > Mathboxes > bj-omex2 | GIF version | ||
| Description: Using bounded set induction and the strong axiom of infinity, ω is a set, that is, we recover ax-infvn 16979 (see bj-2inf 16976 for the equivalence of the latter with bj-omex 16980). (Contributed by BJ, 8-Dec-2019.) (Proof modification is discouraged.) (New usage is discouraged.) |
| Ref | Expression |
|---|---|
| bj-omex2 | ⊢ ω ∈ V |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | ax-inf2 17014 | . . 3 ⊢ ∃𝑎∀𝑥(𝑥 ∈ 𝑎 ↔ (𝑥 = ∅ ∨ ∃𝑦 ∈ 𝑎 𝑥 = suc 𝑦)) | |
| 2 | vex 2824 | . . . 4 ⊢ 𝑎 ∈ V | |
| 3 | bdcv 16886 | . . . . 5 ⊢ BOUNDED 𝑎 | |
| 4 | 3 | bj-inf2vn 17012 | . . . 4 ⊢ (𝑎 ∈ V → (∀𝑥(𝑥 ∈ 𝑎 ↔ (𝑥 = ∅ ∨ ∃𝑦 ∈ 𝑎 𝑥 = suc 𝑦)) → 𝑎 = ω)) |
| 5 | 2, 4 | ax-mp 5 | . . 3 ⊢ (∀𝑥(𝑥 ∈ 𝑎 ↔ (𝑥 = ∅ ∨ ∃𝑦 ∈ 𝑎 𝑥 = suc 𝑦)) → 𝑎 = ω) |
| 6 | 1, 5 | eximii 1655 | . 2 ⊢ ∃𝑎 𝑎 = ω |
| 7 | 6 | issetri 2831 | 1 ⊢ ω ∈ V |
| Colors of variables: wff set class |
| This proof depends on syntax axioms: → wi 4 ↔ wb 105 ∨ wo 720 ∀wal 1400 = wceq 1402 ∈ wcel 2209 ∃wrex 2529 Vcvv 2821 ∅c0 3520 suc csuc 4510 ωcom 4737 |
| This proof depends on axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 106 ax-ia2 107 ax-ia3 108 ax-in1 623 ax-in2 624 ax-io 721 ax-5 1500 ax-7 1501 ax-gen 1502 ax-ie1 1546 ax-ie2 1547 ax-8 1557 ax-10 1558 ax-11 1559 ax-i12 1560 ax-bndl 1562 ax-4 1563 ax-17 1579 ax-i9 1583 ax-ial 1587 ax-i5r 1588 ax-14 2212 ax-ext 2220 ax-nul 4259 ax-pr 4346 ax-un 4578 ax-bd0 16851 ax-bdim 16852 ax-bdor 16854 ax-bdex 16857 ax-bdeq 16858 ax-bdel 16859 ax-bdsep 16922 ax-bdsetind 17006 ax-inf2 17014 |
| This proof depends on definitions: df-bi 117 df-tru 1405 df-nf 1514 df-sb 1816 df-clab 2225 df-cleq 2231 df-clel 2234 df-nfc 2381 df-ral 2533 df-rex 2534 df-rab 2537 df-v 2823 df-dif 3222 df-un 3224 df-in 3226 df-ss 3233 df-nul 3521 df-sn 3715 df-pr 3716 df-uni 3936 df-int 3971 df-suc 4516 df-iom 4738 df-bdc 16879 df-bj-ind 16965 |
| This theorem is used by: (None) |
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