Description: Minus infinity is less than or equal to any extended real. (Contributed by Glauco Siliprandi, 26-Jun-2021)
Ref | Expression | ||
---|---|---|---|
Hypothesis | mnfled.1 | |- ( ph -> A e. RR* ) |
|
Assertion | mnfled | |- ( ph -> -oo <_ A ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | mnfled.1 | |- ( ph -> A e. RR* ) |
|
2 | mnfle | |- ( A e. RR* -> -oo <_ A ) |
|
3 | 1 2 | syl | |- ( ph -> -oo <_ A ) |