Description: The topology of the extended reals is connected. (Contributed by Mario Carneiro, 9-Sep-2015)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | xrconn | ⊢ ( ordTop ‘ ≤ ) ∈ Conn |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | xrhmph | ⊢ II ≃ ( ordTop ‘ ≤ ) | |
| 2 | iiconn | ⊢ II ∈ Conn | |
| 3 | connhmph | ⊢ ( II ≃ ( ordTop ‘ ≤ ) → ( II ∈ Conn → ( ordTop ‘ ≤ ) ∈ Conn ) ) | |
| 4 | 1 2 3 | mp2 | ⊢ ( ordTop ‘ ≤ ) ∈ Conn |