Description: Closure law for real division. (Contributed by SN, 25-Nov-2025)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | redivvald.a | ⊢ ( 𝜑 → 𝐴 ∈ ℝ ) | |
| redivvald.b | ⊢ ( 𝜑 → 𝐵 ∈ ℝ ) | ||
| redivvald.z | ⊢ ( 𝜑 → 𝐵 ≠ 0 ) | ||
| Assertion | sn-redivcld | ⊢ ( 𝜑 → ( 𝐴 /ℝ 𝐵 ) ∈ ℝ ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | redivvald.a | ⊢ ( 𝜑 → 𝐴 ∈ ℝ ) | |
| 2 | redivvald.b | ⊢ ( 𝜑 → 𝐵 ∈ ℝ ) | |
| 3 | redivvald.z | ⊢ ( 𝜑 → 𝐵 ≠ 0 ) | |
| 4 | 1 2 3 | redivvald | ⊢ ( 𝜑 → ( 𝐴 /ℝ 𝐵 ) = ( ℩ 𝑥 ∈ ℝ ( 𝐵 · 𝑥 ) = 𝐴 ) ) |
| 5 | 1 2 3 | rediveud | ⊢ ( 𝜑 → ∃! 𝑥 ∈ ℝ ( 𝐵 · 𝑥 ) = 𝐴 ) |
| 6 | riotacl | ⊢ ( ∃! 𝑥 ∈ ℝ ( 𝐵 · 𝑥 ) = 𝐴 → ( ℩ 𝑥 ∈ ℝ ( 𝐵 · 𝑥 ) = 𝐴 ) ∈ ℝ ) | |
| 7 | 5 6 | syl | ⊢ ( 𝜑 → ( ℩ 𝑥 ∈ ℝ ( 𝐵 · 𝑥 ) = 𝐴 ) ∈ ℝ ) |
| 8 | 4 7 | eqeltrd | ⊢ ( 𝜑 → ( 𝐴 /ℝ 𝐵 ) ∈ ℝ ) |