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Mirrors > Home > ILE Home > Th. List > unidif0 | Unicode version |
Description: The removal of the empty set from a class does not affect its union. (Contributed by NM, 22-Mar-2004.) |
Ref | Expression |
---|---|
unidif0 |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | n0i 3229 | . . . . . . 7 | |
2 | 1 | pm4.71i 371 | . . . . . 6 |
3 | 2 | anbi1i 431 | . . . . 5 |
4 | an32 496 | . . . . 5 | |
5 | anass 381 | . . . . 5 | |
6 | 3, 4, 5 | 3bitr2ri 198 | . . . 4 |
7 | 6 | exbii 1496 | . . 3 |
8 | eluni 3583 | . . . 4 | |
9 | eldif 2927 | . . . . . . 7 | |
10 | velsn 3392 | . . . . . . . . 9 | |
11 | 10 | notbii 594 | . . . . . . . 8 |
12 | 11 | anbi2i 430 | . . . . . . 7 |
13 | 9, 12 | bitri 173 | . . . . . 6 |
14 | 13 | anbi2i 430 | . . . . 5 |
15 | 14 | exbii 1496 | . . . 4 |
16 | 8, 15 | bitri 173 | . . 3 |
17 | eluni 3583 | . . 3 | |
18 | 7, 16, 17 | 3bitr4i 201 | . 2 |
19 | 18 | eqriv 2037 | 1 |
Colors of variables: wff set class |
Syntax hints: wn 3 wa 97 wceq 1243 wex 1381 wcel 1393 cdif 2914 c0 3224 csn 3375 cuni 3580 |
This theorem was proved from axioms: ax-1 5 ax-2 6 ax-mp 7 ax-ia1 99 ax-ia2 100 ax-ia3 101 ax-in1 544 ax-in2 545 ax-io 630 ax-5 1336 ax-7 1337 ax-gen 1338 ax-ie1 1382 ax-ie2 1383 ax-8 1395 ax-10 1396 ax-11 1397 ax-i12 1398 ax-bndl 1399 ax-4 1400 ax-17 1419 ax-i9 1423 ax-ial 1427 ax-i5r 1428 ax-ext 2022 |
This theorem depends on definitions: df-bi 110 df-tru 1246 df-nf 1350 df-sb 1646 df-clab 2027 df-cleq 2033 df-clel 2036 df-nfc 2167 df-v 2559 df-dif 2920 df-nul 3225 df-sn 3381 df-uni 3581 |
This theorem is referenced by: (None) |
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