Description: The underlying set belongs to the filter. (Contributed by FL, 20-Jul-2007) (Revised by Stefan O'Rear, 28-Jul-2015)
Ref | Expression | ||
---|---|---|---|
Assertion | filtop | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | filfbas | |
|
2 | fbasne0 | |
|
3 | 1 2 | syl | |
4 | n0 | |
|
5 | filelss | |
|
6 | ssid | |
|
7 | filss | |
|
8 | 7 | 3exp2 | |
9 | 8 | imp | |
10 | 6 9 | mpi | |
11 | 5 10 | mpd | |
12 | 11 | ex | |
13 | 12 | exlimdv | |
14 | 4 13 | biimtrid | |
15 | 3 14 | mpd | |