Description: Natural multiplication by zero. Deduction form. (Contributed by Scott Fenton, 30-Jul-2026)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | nmul.1 | ⊢ ( 𝜑 → 𝐴 ∈ On ) | |
| Assertion | nmulr0d | ⊢ ( 𝜑 → ( 𝐴 ·no ∅ ) = ∅ ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | nmul.1 | ⊢ ( 𝜑 → 𝐴 ∈ On ) | |
| 2 | nmulr0 | ⊢ ( 𝐴 ∈ On → ( 𝐴 ·no ∅ ) = ∅ ) | |
| 3 | 1 2 | syl | ⊢ ( 𝜑 → ( 𝐴 ·no ∅ ) = ∅ ) |