Description: Comparison of a number and its negative to zero. (Contributed by Mario Carneiro, 27-May-2016)
Ref | Expression | ||
---|---|---|---|
Hypothesis | leidd.1 | |- ( ph -> A e. RR ) |
|
Assertion | le0neg2d | |- ( ph -> ( 0 <_ A <-> -u A <_ 0 ) ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | leidd.1 | |- ( ph -> A e. RR ) |
|
2 | le0neg2 | |- ( A e. RR -> ( 0 <_ A <-> -u A <_ 0 ) ) |
|
3 | 1 2 | syl | |- ( ph -> ( 0 <_ A <-> -u A <_ 0 ) ) |