Description: The sum of nonnegative extended reals is nonnegative. (Contributed by Mario Carneiro, 21-Aug-2015)
Ref | Expression | ||
---|---|---|---|
Assertion | xaddge0 | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | 0xr | |
|
2 | 1 | a1i | |
3 | simplr | |
|
4 | xaddcl | |
|
5 | 4 | adantr | |
6 | simprr | |
|
7 | xaddlid | |
|
8 | 3 7 | syl | |
9 | simpll | |
|
10 | simprl | |
|
11 | xleadd1a | |
|
12 | 2 9 3 10 11 | syl31anc | |
13 | 8 12 | eqbrtrrd | |
14 | 2 3 5 6 13 | xrletrd | |