Description: A filter base on a set is a subset of the power set. (Contributed by Stefan O'Rear, 28-Jul-2015)
Ref | Expression | ||
---|---|---|---|
Assertion | fbsspw | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | elfvdm | |
|
2 | isfbas | |
|
3 | 1 2 | syl | |
4 | 3 | ibi | |
5 | 4 | simpld | |