Description: Minus infinity is less than any (finite) real. (Contributed by Glauco Siliprandi, 11-Dec-2019)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | mnfltd.a | ⊢ ( 𝜑 → 𝐴 ∈ ℝ ) | |
| Assertion | mnfltd | ⊢ ( 𝜑 → -∞ < 𝐴 ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | mnfltd.a | ⊢ ( 𝜑 → 𝐴 ∈ ℝ ) | |
| 2 | mnflt | ⊢ ( 𝐴 ∈ ℝ → -∞ < 𝐴 ) | |
| 3 | 1 2 | syl | ⊢ ( 𝜑 → -∞ < 𝐴 ) |