Description: Division of both sides of 'less than' by a positive number. (Contributed by NM, 16-May-1999)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | ltplus1.1 | |- A e. RR | |
| prodgt0.2 | |- B e. RR | ||
| ltmul1.3 | |- C e. RR | ||
| ltmul1i.4 | |- 0 < C | ||
| Assertion | ltdiv1ii | |- ( A < B <-> ( A / C ) < ( B / C ) ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | ltplus1.1 | |- A e. RR | |
| 2 | prodgt0.2 | |- B e. RR | |
| 3 | ltmul1.3 | |- C e. RR | |
| 4 | ltmul1i.4 | |- 0 < C | |
| 5 | 1 2 3 | ltdiv1i | |- ( 0 < C -> ( A < B <-> ( A / C ) < ( B / C ) ) ) | 
| 6 | 4 5 | ax-mp | |- ( A < B <-> ( A / C ) < ( B / C ) ) |