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Mirrors > Home > MPE Home > Th. List > Mathboxes > df-toplnd | Structured version Visualization version Unicode version |
Description: A topology is Lindelöf iff every open cover has a countable subcover. (Contributed by Stefan O'Rear, 8-Jan-2015.) |
Ref | Expression |
---|---|
df-toplnd | TopLnd |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ctoplnd 37792 | . 2 TopLnd | |
2 | vx | . . . . . . . 8 | |
3 | 2 | cv 1482 | . . . . . . 7 |
4 | 3 | cuni 4436 | . . . . . 6 |
5 | vy | . . . . . . . 8 | |
6 | 5 | cv 1482 | . . . . . . 7 |
7 | 6 | cuni 4436 | . . . . . 6 |
8 | 4, 7 | wceq 1483 | . . . . 5 |
9 | vz | . . . . . . . . 9 | |
10 | 9 | cv 1482 | . . . . . . . 8 |
11 | com 7065 | . . . . . . . 8 | |
12 | cdom 7953 | . . . . . . . 8 | |
13 | 10, 11, 12 | wbr 4653 | . . . . . . 7 |
14 | 10 | cuni 4436 | . . . . . . . 8 |
15 | 4, 14 | wceq 1483 | . . . . . . 7 |
16 | 13, 15 | wa 384 | . . . . . 6 |
17 | 3 | cpw 4158 | . . . . . 6 |
18 | 16, 9, 17 | wrex 2913 | . . . . 5 |
19 | 8, 18 | wi 4 | . . . 4 |
20 | 19, 5, 17 | wral 2912 | . . 3 |
21 | ctop 20698 | . . 3 | |
22 | 20, 2, 21 | crab 2916 | . 2 |
23 | 1, 22 | wceq 1483 | 1 TopLnd |
Colors of variables: wff setvar class |
This definition is referenced by: (None) |
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