Description: Reverse closure of the closed set operation. (Contributed by Stefan O'Rear, 22-Feb-2015)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | cldrcl | ⊢ ( 𝐶 ∈ ( Clsd ‘ 𝐽 ) → 𝐽 ∈ Top ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | elfvdm | ⊢ ( 𝐶 ∈ ( Clsd ‘ 𝐽 ) → 𝐽 ∈ dom Clsd ) | |
| 2 | fncld | ⊢ Clsd Fn Top | |
| 3 | 2 | fndmi | ⊢ dom Clsd = Top |
| 4 | 1 3 | eleqtrdi | ⊢ ( 𝐶 ∈ ( Clsd ‘ 𝐽 ) → 𝐽 ∈ Top ) |