Description: Absolute value of a nonpositive difference. (Contributed by FL, 3-Jan-2008)
Ref | Expression | ||
---|---|---|---|
Assertion | abssuble0 | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | recn | |
|
2 | recn | |
|
3 | abssub | |
|
4 | 1 2 3 | syl2an | |
5 | 4 | 3adant3 | |
6 | abssubge0 | |
|
7 | 5 6 | eqtrd | |