Description: Reverse closure for the homeomorphic predicate. (Contributed by Mario Carneiro, 22-Aug-2015)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | hmphtop | ⊢ ( 𝐽 ≃ 𝐾 → ( 𝐽 ∈ Top ∧ 𝐾 ∈ Top ) ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | df-hmph | ⊢ ≃ = ( ◡ Homeo “ ( V ∖ 1o ) ) | |
| 2 | cnvimass | ⊢ ( ◡ Homeo “ ( V ∖ 1o ) ) ⊆ dom Homeo | |
| 3 | hmeofn | ⊢ Homeo Fn ( Top × Top ) | |
| 4 | fndm | ⊢ ( Homeo Fn ( Top × Top ) → dom Homeo = ( Top × Top ) ) | |
| 5 | 3 4 | ax-mp | ⊢ dom Homeo = ( Top × Top ) | 
| 6 | 2 5 | sseqtri | ⊢ ( ◡ Homeo “ ( V ∖ 1o ) ) ⊆ ( Top × Top ) | 
| 7 | 1 6 | eqsstri | ⊢ ≃ ⊆ ( Top × Top ) | 
| 8 | 7 | brel | ⊢ ( 𝐽 ≃ 𝐾 → ( 𝐽 ∈ Top ∧ 𝐾 ∈ Top ) ) |