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Mirrors > Home > MPE Home > Th. List > eltg3 | Structured version Visualization version GIF version |
Description: Membership in a topology generated by a basis. (Contributed by NM, 15-Jul-2006.) (Proof shortened by Mario Carneiro, 30-Aug-2015.) |
Ref | Expression |
---|---|
eltg3 | ⊢ (𝐵 ∈ 𝑉 → (𝐴 ∈ (topGen‘𝐵) ↔ ∃𝑥(𝑥 ⊆ 𝐵 ∧ 𝐴 = ∪ 𝑥))) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | elfvdm 6928 | . . . 4 ⊢ (𝐴 ∈ (topGen‘𝐵) → 𝐵 ∈ dom topGen) | |
2 | inex1g 5319 | . . . 4 ⊢ (𝐵 ∈ dom topGen → (𝐵 ∩ 𝒫 𝐴) ∈ V) | |
3 | 1, 2 | syl 17 | . . 3 ⊢ (𝐴 ∈ (topGen‘𝐵) → (𝐵 ∩ 𝒫 𝐴) ∈ V) |
4 | eltg4i 22696 | . . 3 ⊢ (𝐴 ∈ (topGen‘𝐵) → 𝐴 = ∪ (𝐵 ∩ 𝒫 𝐴)) | |
5 | inss1 4228 | . . . . . 6 ⊢ (𝐵 ∩ 𝒫 𝐴) ⊆ 𝐵 | |
6 | sseq1 4007 | . . . . . 6 ⊢ (𝑥 = (𝐵 ∩ 𝒫 𝐴) → (𝑥 ⊆ 𝐵 ↔ (𝐵 ∩ 𝒫 𝐴) ⊆ 𝐵)) | |
7 | 5, 6 | mpbiri 258 | . . . . 5 ⊢ (𝑥 = (𝐵 ∩ 𝒫 𝐴) → 𝑥 ⊆ 𝐵) |
8 | 7 | biantrurd 532 | . . . 4 ⊢ (𝑥 = (𝐵 ∩ 𝒫 𝐴) → (𝐴 = ∪ 𝑥 ↔ (𝑥 ⊆ 𝐵 ∧ 𝐴 = ∪ 𝑥))) |
9 | unieq 4919 | . . . . 5 ⊢ (𝑥 = (𝐵 ∩ 𝒫 𝐴) → ∪ 𝑥 = ∪ (𝐵 ∩ 𝒫 𝐴)) | |
10 | 9 | eqeq2d 2742 | . . . 4 ⊢ (𝑥 = (𝐵 ∩ 𝒫 𝐴) → (𝐴 = ∪ 𝑥 ↔ 𝐴 = ∪ (𝐵 ∩ 𝒫 𝐴))) |
11 | 8, 10 | bitr3d 281 | . . 3 ⊢ (𝑥 = (𝐵 ∩ 𝒫 𝐴) → ((𝑥 ⊆ 𝐵 ∧ 𝐴 = ∪ 𝑥) ↔ 𝐴 = ∪ (𝐵 ∩ 𝒫 𝐴))) |
12 | 3, 4, 11 | spcedv 3588 | . 2 ⊢ (𝐴 ∈ (topGen‘𝐵) → ∃𝑥(𝑥 ⊆ 𝐵 ∧ 𝐴 = ∪ 𝑥)) |
13 | eltg3i 22697 | . . . . 5 ⊢ ((𝐵 ∈ 𝑉 ∧ 𝑥 ⊆ 𝐵) → ∪ 𝑥 ∈ (topGen‘𝐵)) | |
14 | eleq1 2820 | . . . . 5 ⊢ (𝐴 = ∪ 𝑥 → (𝐴 ∈ (topGen‘𝐵) ↔ ∪ 𝑥 ∈ (topGen‘𝐵))) | |
15 | 13, 14 | syl5ibrcom 246 | . . . 4 ⊢ ((𝐵 ∈ 𝑉 ∧ 𝑥 ⊆ 𝐵) → (𝐴 = ∪ 𝑥 → 𝐴 ∈ (topGen‘𝐵))) |
16 | 15 | expimpd 453 | . . 3 ⊢ (𝐵 ∈ 𝑉 → ((𝑥 ⊆ 𝐵 ∧ 𝐴 = ∪ 𝑥) → 𝐴 ∈ (topGen‘𝐵))) |
17 | 16 | exlimdv 1935 | . 2 ⊢ (𝐵 ∈ 𝑉 → (∃𝑥(𝑥 ⊆ 𝐵 ∧ 𝐴 = ∪ 𝑥) → 𝐴 ∈ (topGen‘𝐵))) |
18 | 12, 17 | impbid2 225 | 1 ⊢ (𝐵 ∈ 𝑉 → (𝐴 ∈ (topGen‘𝐵) ↔ ∃𝑥(𝑥 ⊆ 𝐵 ∧ 𝐴 = ∪ 𝑥))) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ↔ wb 205 ∧ wa 395 = wceq 1540 ∃wex 1780 ∈ wcel 2105 Vcvv 3473 ∩ cin 3947 ⊆ wss 3948 𝒫 cpw 4602 ∪ cuni 4908 dom cdm 5676 ‘cfv 6543 topGenctg 17390 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1796 ax-4 1810 ax-5 1912 ax-6 1970 ax-7 2010 ax-8 2107 ax-9 2115 ax-10 2136 ax-11 2153 ax-12 2170 ax-ext 2702 ax-sep 5299 ax-nul 5306 ax-pow 5363 ax-pr 5427 ax-un 7729 |
This theorem depends on definitions: df-bi 206 df-an 396 df-or 845 df-3an 1088 df-tru 1543 df-fal 1553 df-ex 1781 df-nf 1785 df-sb 2067 df-mo 2533 df-eu 2562 df-clab 2709 df-cleq 2723 df-clel 2809 df-nfc 2884 df-ral 3061 df-rex 3070 df-rab 3432 df-v 3475 df-dif 3951 df-un 3953 df-in 3955 df-ss 3965 df-nul 4323 df-if 4529 df-pw 4604 df-sn 4629 df-pr 4631 df-op 4635 df-uni 4909 df-br 5149 df-opab 5211 df-mpt 5232 df-id 5574 df-xp 5682 df-rel 5683 df-cnv 5684 df-co 5685 df-dm 5686 df-iota 6495 df-fun 6545 df-fv 6551 df-topgen 17396 |
This theorem is referenced by: tgval3 22699 tgtop 22709 eltop3 22712 tgidm 22716 bastop1 22729 tgrest 22896 tgcn 22989 txbasval 23343 opnmblALT 25365 mbfimaopnlem 25417 isfne3 35544 fneuni 35548 dissneqlem 36537 tgqioo2 44571 |
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