Metamath Proof Explorer


Theorem rehalfcl

Description: Real closure of half. (Contributed by NM, 1-Jan-2006)

Ref Expression
Assertion rehalfcl ⊢ A ∈ ℝ → A 2 ∈ ℝ

Proof

Step Hyp Ref Expression
1 2re ⊢ 2 ∈ ℝ
2 2ne0 ⊢ 2 ≠ 0
3 redivcl ⊢ A ∈ ℝ ∧ 2 ∈ ℝ ∧ 2 ≠ 0 → A 2 ∈ ℝ
4 1 2 3 mp3an23 ⊢ A ∈ ℝ → A 2 ∈ ℝ