Metamath Proof Explorer


Theorem blcntr

Description: A ball contains its center. (Contributed by NM, 2-Sep-2006) (Revised by Mario Carneiro, 12-Nov-2013)

Ref Expression
Assertion blcntr ⊢ D ∈ ∞Met ⁡ X ∧ P ∈ X ∧ R ∈ ℝ + → P ∈ P ball ⁡ D R

Proof

Step Hyp Ref Expression
1 rpxr ⊢ R ∈ ℝ + → R ∈ ℝ *
2 rpgt0 ⊢ R ∈ ℝ + → 0 < R
3 1 2 jca ⊢ R ∈ ℝ + → R ∈ ℝ * ∧ 0 < R
4 xblcntr ⊢ D ∈ ∞Met ⁡ X ∧ P ∈ X ∧ R ∈ ℝ * ∧ 0 < R → P ∈ P ball ⁡ D R
5 3 4 syl3an3 ⊢ D ∈ ∞Met ⁡ X ∧ P ∈ X ∧ R ∈ ℝ + → P ∈ P ball ⁡ D R