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Mirrors > Home > ILE Home > Th. List > 0ntop | GIF version |
Description: The empty set is not a topology. (Contributed by FL, 1-Jun-2008.) |
Ref | Expression |
---|---|
0ntop | ⊢ ¬ ∅ ∈ Top |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | noel 3314 | . 2 ⊢ ¬ ∅ ∈ ∅ | |
2 | 0opn 11955 | . 2 ⊢ (∅ ∈ Top → ∅ ∈ ∅) | |
3 | 1, 2 | mto 629 | 1 ⊢ ¬ ∅ ∈ Top |
Colors of variables: wff set class |
Syntax hints: ¬ wn 3 ∈ wcel 1448 ∅c0 3310 Topctop 11946 |
This theorem was proved from axioms: ax-1 5 ax-2 6 ax-mp 7 ax-ia1 105 ax-ia2 106 ax-ia3 107 ax-in1 584 ax-in2 585 ax-io 671 ax-5 1391 ax-7 1392 ax-gen 1393 ax-ie1 1437 ax-ie2 1438 ax-8 1450 ax-10 1451 ax-11 1452 ax-i12 1453 ax-bndl 1454 ax-4 1455 ax-17 1474 ax-i9 1478 ax-ial 1482 ax-i5r 1483 ax-ext 2082 ax-sep 3986 |
This theorem depends on definitions: df-bi 116 df-tru 1302 df-fal 1305 df-nf 1405 df-sb 1704 df-clab 2087 df-cleq 2093 df-clel 2096 df-nfc 2229 df-ral 2380 df-rex 2381 df-v 2643 df-dif 3023 df-in 3027 df-ss 3034 df-nul 3311 df-pw 3459 df-sn 3480 df-uni 3684 df-top 11947 |
This theorem is referenced by: (None) |
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