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 ) |