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| Mirrors > Home > MPE Home > Th. List > eltg3i | Structured version Visualization version GIF version | ||
| Description: The union of a set of basic open sets is in the generated topology. (Contributed by Mario Carneiro, 30-Aug-2015.) | 
| Ref | Expression | 
|---|---|
| eltg3i | ⊢ ((𝐵 ∈ 𝑉 ∧ 𝐴 ⊆ 𝐵) → ∪ 𝐴 ∈ (topGen‘𝐵)) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | simpr 484 | . . . 4 ⊢ ((𝐵 ∈ 𝑉 ∧ 𝐴 ⊆ 𝐵) → 𝐴 ⊆ 𝐵) | |
| 2 | pwuni 4944 | . . . 4 ⊢ 𝐴 ⊆ 𝒫 ∪ 𝐴 | |
| 3 | ssin 4238 | . . . 4 ⊢ ((𝐴 ⊆ 𝐵 ∧ 𝐴 ⊆ 𝒫 ∪ 𝐴) ↔ 𝐴 ⊆ (𝐵 ∩ 𝒫 ∪ 𝐴)) | |
| 4 | 1, 2, 3 | sylanblc 589 | . . 3 ⊢ ((𝐵 ∈ 𝑉 ∧ 𝐴 ⊆ 𝐵) → 𝐴 ⊆ (𝐵 ∩ 𝒫 ∪ 𝐴)) | 
| 5 | 4 | unissd 4916 | . 2 ⊢ ((𝐵 ∈ 𝑉 ∧ 𝐴 ⊆ 𝐵) → ∪ 𝐴 ⊆ ∪ (𝐵 ∩ 𝒫 ∪ 𝐴)) | 
| 6 | eltg 22965 | . . 3 ⊢ (𝐵 ∈ 𝑉 → (∪ 𝐴 ∈ (topGen‘𝐵) ↔ ∪ 𝐴 ⊆ ∪ (𝐵 ∩ 𝒫 ∪ 𝐴))) | |
| 7 | 6 | adantr 480 | . 2 ⊢ ((𝐵 ∈ 𝑉 ∧ 𝐴 ⊆ 𝐵) → (∪ 𝐴 ∈ (topGen‘𝐵) ↔ ∪ 𝐴 ⊆ ∪ (𝐵 ∩ 𝒫 ∪ 𝐴))) | 
| 8 | 5, 7 | mpbird 257 | 1 ⊢ ((𝐵 ∈ 𝑉 ∧ 𝐴 ⊆ 𝐵) → ∪ 𝐴 ∈ (topGen‘𝐵)) | 
| Colors of variables: wff setvar class | 
| Syntax hints: → wi 4 ↔ wb 206 ∧ wa 395 ∈ wcel 2107 ∩ cin 3949 ⊆ wss 3950 𝒫 cpw 4599 ∪ cuni 4906 ‘cfv 6560 topGenctg 17483 | 
| This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1794 ax-4 1808 ax-5 1909 ax-6 1966 ax-7 2006 ax-8 2109 ax-9 2117 ax-10 2140 ax-11 2156 ax-12 2176 ax-ext 2707 ax-sep 5295 ax-nul 5305 ax-pow 5364 ax-pr 5431 ax-un 7756 | 
| This theorem depends on definitions: df-bi 207 df-an 396 df-or 848 df-3an 1088 df-tru 1542 df-fal 1552 df-ex 1779 df-nf 1783 df-sb 2064 df-mo 2539 df-eu 2568 df-clab 2714 df-cleq 2728 df-clel 2815 df-nfc 2891 df-ral 3061 df-rex 3070 df-rab 3436 df-v 3481 df-dif 3953 df-un 3955 df-in 3957 df-ss 3967 df-nul 4333 df-if 4525 df-pw 4601 df-sn 4626 df-pr 4628 df-op 4632 df-uni 4907 df-br 5143 df-opab 5205 df-mpt 5225 df-id 5577 df-xp 5690 df-rel 5691 df-cnv 5692 df-co 5693 df-dm 5694 df-iota 6513 df-fun 6562 df-fv 6568 df-topgen 17489 | 
| This theorem is referenced by: eltg3 22970 tgiun 22987 tgidm 22988 tgrest 23168 leordtval2 23221 fnemeet1 36368 fnejoin2 36371 ontgval 36433 | 
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