Metamath Proof Explorer


Theorem hmphtop

Description: Reverse closure for the homeomorphic predicate. (Contributed by Mario Carneiro, 22-Aug-2015)

Ref Expression
Assertion hmphtop ⊢ J ≃ K → J ∈ Top ∧ K ∈ Top

Proof

Step Hyp Ref Expression
1 df-hmph ⊢ ≃ = Homeo -1 V ∖ 1 𝑜
2 cnvimass ⊢ Homeo -1 V ∖ 1 𝑜 ⊆ 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 -1 V ∖ 1 𝑜 ⊆ Top × Top
7 1 6 eqsstri ⊢ ≃ ⊆ Top × Top
8 7 brel ⊢ J ≃ K → J ∈ Top ∧ K ∈ Top