"Di" is strictly related to "più" in this case, because it means that he wants his workers to work harder.
If you want to put a comparative, you take out "di" and put the comparison element:
- "Lavorate più di ieri" ( You work more than yesterday ) , "Lavorate più di loro" ( You work more than them )
Yes, in this case it is simply wrong.
Anyway, I have to correct my self: I wrote that with the comparative you take out "di"; actually it remains, but changes position:
"Lavorate di più!" = "Work more/harder!" ( Imperative )
"Lavorate più di loro" = "You work more then them" ( Comparative )
"Lavorate meno di noi" = "You work less the us" ( Comparative )
Ciao a tutti, would anybody know the rule to use "di più" after a verb. I have seen both cases, in some "di" is not used and in some is used like in the above sentence "Lavorate di più"? It is not clear to me how to establish the rule for when to use "di" and when not to use it. Grazie!