Description: A filter is a subset of the power set of the base set. (Contributed by Stefan O'Rear, 28-Jul-2015)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | filsspw | ⊢ ( 𝐹 ∈ ( Fil ‘ 𝑋 ) → 𝐹 ⊆ 𝒫 𝑋 ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | filfbas | ⊢ ( 𝐹 ∈ ( Fil ‘ 𝑋 ) → 𝐹 ∈ ( fBas ‘ 𝑋 ) ) | |
| 2 | fbsspw | ⊢ ( 𝐹 ∈ ( fBas ‘ 𝑋 ) → 𝐹 ⊆ 𝒫 𝑋 ) | |
| 3 | 1 2 | syl | ⊢ ( 𝐹 ∈ ( Fil ‘ 𝑋 ) → 𝐹 ⊆ 𝒫 𝑋 ) |