Metamath Proof Explorer


Theorem xrge0tps

Description: The extended nonnegative real numbers monoid forms a topological space. (Contributed by Thierry Arnoux, 19-Jun-2017)

Ref Expression
Assertion xrge0tps ( ℝ*𝑠s ( 0 [,] +∞ ) ) ∈ TopSp

Proof

Step Hyp Ref Expression
1 xrstps *𝑠 ∈ TopSp
2 ovex ( 0 [,] +∞ ) ∈ V
3 resstps ( ( ℝ*𝑠 ∈ TopSp ∧ ( 0 [,] +∞ ) ∈ V ) → ( ℝ*𝑠s ( 0 [,] +∞ ) ) ∈ TopSp )
4 1 2 3 mp2an ( ℝ*𝑠s ( 0 [,] +∞ ) ) ∈ TopSp