Intuitionistic Logic Explorer |
< Previous
Next >
Nearby theorems |
||
Mirrors > Home > ILE Home > Th. List > uni0b | Unicode version |
Description: The union of a set is empty iff the set is included in the singleton of the empty set. (Contributed by NM, 12-Sep-2004.) |
Ref | Expression |
---|---|
uni0b |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | eq0 3266 | . . . 4 | |
2 | 1 | ralbii 2372 | . . 3 |
3 | ralcom4 2621 | . . 3 | |
4 | 2, 3 | bitri 182 | . 2 |
5 | dfss3 2989 | . . 3 | |
6 | velsn 3415 | . . . 4 | |
7 | 6 | ralbii 2372 | . . 3 |
8 | 5, 7 | bitri 182 | . 2 |
9 | eluni2 3605 | . . . . 5 | |
10 | 9 | notbii 626 | . . . 4 |
11 | 10 | albii 1399 | . . 3 |
12 | eq0 3266 | . . 3 | |
13 | ralnex 2358 | . . . 4 | |
14 | 13 | albii 1399 | . . 3 |
15 | 11, 12, 14 | 3bitr4i 210 | . 2 |
16 | 4, 8, 15 | 3bitr4ri 211 | 1 |
Colors of variables: wff set class |
Syntax hints: wn 3 wb 103 wal 1282 wceq 1284 wcel 1433 wral 2348 wrex 2349 wss 2973 c0 3251 csn 3398 cuni 3601 |
This theorem was proved from axioms: ax-1 5 ax-2 6 ax-mp 7 ax-ia1 104 ax-ia2 105 ax-ia3 106 ax-in1 576 ax-in2 577 ax-io 662 ax-5 1376 ax-7 1377 ax-gen 1378 ax-ie1 1422 ax-ie2 1423 ax-8 1435 ax-10 1436 ax-11 1437 ax-i12 1438 ax-bndl 1439 ax-4 1440 ax-17 1459 ax-i9 1463 ax-ial 1467 ax-i5r 1468 ax-ext 2063 |
This theorem depends on definitions: df-bi 115 df-tru 1287 df-fal 1290 df-nf 1390 df-sb 1686 df-clab 2068 df-cleq 2074 df-clel 2077 df-nfc 2208 df-ral 2353 df-rex 2354 df-v 2603 df-dif 2975 df-in 2979 df-ss 2986 df-nul 3252 df-sn 3404 df-uni 3602 |
This theorem is referenced by: uni0c 3627 uni0 3628 |
Copyright terms: Public domain | W3C validator |