Metamath Proof Explorer


Theorem sn-rediv1d

Description: A number divided by 1 is itself. (Contributed by SN, 2-Apr-2026)

Ref Expression
Hypothesis sn-rediv1d.a ⊢ φ → A ∈ ℝ
Assertion sn-rediv1d ⊢ φ → A / ℝ 1 = A

Proof

Step Hyp Ref Expression
1 sn-rediv1d.a ⊢ φ → A ∈ ℝ
2 remullid ⊢ A ∈ ℝ → 1 ⁢ A = A
3 1 2 syl ⊢ φ → 1 ⁢ A = A
4 1red ⊢ φ → 1 ∈ ℝ
5 ax-1ne0 ⊢ 1 ≠ 0
6 5 a1i ⊢ φ → 1 ≠ 0
7 1 1 4 6 redivmuld ⊢ φ → A / ℝ 1 = A ↔ 1 ⁢ A = A
8 3 7 mpbird ⊢ φ → A / ℝ 1 = A