Description: The predicate "is a nonnegative real". (Contributed by Jeff Madsen, 2-Sep-2009) (Proof shortened by Mario Carneiro, 18-Jun-2014)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | elrege0 | |- ( A e. ( 0 [,) +oo ) <-> ( A e. RR /\ 0 <_ A ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | 0re | |- 0 e. RR |
|
| 2 | elicopnf | |- ( 0 e. RR -> ( A e. ( 0 [,) +oo ) <-> ( A e. RR /\ 0 <_ A ) ) ) |
|
| 3 | 1 2 | ax-mp | |- ( A e. ( 0 [,) +oo ) <-> ( A e. RR /\ 0 <_ A ) ) |