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Mirrors > Home > ILE Home > Th. List > uniopn | Unicode version |
Description: The union of a subset of a topology (that is, the union of any family of open sets of a topology) is an open set. (Contributed by Stefan Allan, 27-Feb-2006.) |
Ref | Expression |
---|---|
uniopn |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | istopg 12169 | . . . . 5 | |
2 | 1 | ibi 175 | . . . 4 |
3 | 2 | simpld 111 | . . 3 |
4 | elpw2g 4081 | . . . . . . . 8 | |
5 | 4 | biimpar 295 | . . . . . . 7 |
6 | sseq1 3120 | . . . . . . . . 9 | |
7 | unieq 3745 | . . . . . . . . . 10 | |
8 | 7 | eleq1d 2208 | . . . . . . . . 9 |
9 | 6, 8 | imbi12d 233 | . . . . . . . 8 |
10 | 9 | spcgv 2773 | . . . . . . 7 |
11 | 5, 10 | syl 14 | . . . . . 6 |
12 | 11 | com23 78 | . . . . 5 |
13 | 12 | ex 114 | . . . 4 |
14 | 13 | pm2.43d 50 | . . 3 |
15 | 3, 14 | mpid 42 | . 2 |
16 | 15 | imp 123 | 1 |
Colors of variables: wff set class |
Syntax hints: wi 4 wa 103 wal 1329 wceq 1331 wcel 1480 wral 2416 cin 3070 wss 3071 cpw 3510 cuni 3736 ctop 12167 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 105 ax-ia2 106 ax-ia3 107 ax-io 698 ax-5 1423 ax-7 1424 ax-gen 1425 ax-ie1 1469 ax-ie2 1470 ax-8 1482 ax-10 1483 ax-11 1484 ax-i12 1485 ax-bndl 1486 ax-4 1487 ax-17 1506 ax-i9 1510 ax-ial 1514 ax-i5r 1515 ax-ext 2121 ax-sep 4046 |
This theorem depends on definitions: df-bi 116 df-tru 1334 df-nf 1437 df-sb 1736 df-clab 2126 df-cleq 2132 df-clel 2135 df-nfc 2270 df-ral 2421 df-rex 2422 df-v 2688 df-in 3077 df-ss 3084 df-pw 3512 df-uni 3737 df-top 12168 |
This theorem is referenced by: iunopn 12172 unopn 12175 0opn 12176 topopn 12178 tgtop 12240 ntropn 12289 neipsm 12326 unimopn 12658 metrest 12678 cnopncntop 12709 |
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