Metamath Proof Explorer


Theorem letop

Description: The topology of the extended reals. (Contributed by Mario Carneiro, 3-Sep-2015)

Ref Expression
Assertion letop ⊢ ordTop ⁡ ≤ ∈ Top

Proof

Step Hyp Ref Expression
1 letopon ⊢ ordTop ⁡ ≤ ∈ TopOn ⁡ ℝ *
2 1 topontopi ⊢ ordTop ⁡ ≤ ∈ Top