Metamath Proof Explorer


Theorem rrxunitopnfi

Description: The base set of the standard topology on the space of n-dimensional Real numbers. (Contributed by Glauco Siliprandi, 24-Dec-2020)

Ref Expression
Assertion rrxunitopnfi ⊢ X ∈ Fin → ⋃ TopOpen ⁡ X = ℝ X

Proof

Step Hyp Ref Expression
1 eqidd ⊢ X ∈ Fin → ℝ X = ℝ X
2 eqid ⊢ TopOpen ⁡ X = TopOpen ⁡ X
3 2 rrxtoponfi ⊢ X ∈ Fin → TopOpen ⁡ X ∈ TopOn ⁡ ℝ X
4 toponuni ⊢ TopOpen ⁡ X ∈ TopOn ⁡ ℝ X → ℝ X = ⋃ TopOpen ⁡ X
5 3 4 syl ⊢ X ∈ Fin → ℝ X = ⋃ TopOpen ⁡ X
6 1 5 eqtr2d ⊢ X ∈ Fin → ⋃ TopOpen ⁡ X = ℝ X