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Mirrors > Home > MPE Home > Th. List > uniexb | Structured version Visualization version GIF version |
Description: The Axiom of Union and its converse. A class is a set iff its union is a set. (Contributed by NM, 11-Nov-2003.) |
Ref | Expression |
---|---|
uniexb | ⊢ (𝐴 ∈ V ↔ ∪ 𝐴 ∈ V) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | uniexg 6853 | . 2 ⊢ (𝐴 ∈ V → ∪ 𝐴 ∈ V) | |
2 | pwuni 4825 | . . 3 ⊢ 𝐴 ⊆ 𝒫 ∪ 𝐴 | |
3 | pwexg 4776 | . . 3 ⊢ (∪ 𝐴 ∈ V → 𝒫 ∪ 𝐴 ∈ V) | |
4 | ssexg 4732 | . . 3 ⊢ ((𝐴 ⊆ 𝒫 ∪ 𝐴 ∧ 𝒫 ∪ 𝐴 ∈ V) → 𝐴 ∈ V) | |
5 | 2, 3, 4 | sylancr 694 | . 2 ⊢ (∪ 𝐴 ∈ V → 𝐴 ∈ V) |
6 | 1, 5 | impbii 198 | 1 ⊢ (𝐴 ∈ V ↔ ∪ 𝐴 ∈ V) |
Colors of variables: wff setvar class |
Syntax hints: ↔ wb 195 ∈ wcel 1977 Vcvv 3173 ⊆ wss 3540 𝒫 cpw 4108 ∪ cuni 4372 |
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-8 1979 ax-9 1986 ax-10 2006 ax-11 2021 ax-12 2034 ax-13 2234 ax-ext 2590 ax-sep 4709 ax-pow 4769 ax-un 6847 |
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-rex 2902 df-v 3175 df-in 3547 df-ss 3554 df-pw 4110 df-uni 4373 |
This theorem is referenced by: pwexb 6867 ssonprc 6884 ixpexg 7818 rankuni 8609 ac5num 8742 unialeph 8807 ttukeylem1 9214 tgss2 20602 ordtbas2 20805 ordtbas 20806 ordttopon 20807 ordtopn1 20808 ordtopn2 20809 ordtrest2 20818 isref 21122 islocfin 21130 txbasex 21179 ptbasin2 21191 ordthmeolem 21414 alexsublem 21658 alexsub 21659 alexsubb 21660 ussid 21874 ordtrest2NEW 29297 omsfval 29683 brbigcup 31175 isfne 31504 isfne4 31505 isfne4b 31506 fnessref 31522 neibastop1 31524 fnejoin2 31534 bj-restv 32229 prtex 33183 |
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